A pattern governing supply and demand changes

[solo]

After Trade is discovered and before any trading takes place, the timing of the seemingly spontaneous changes to the supply and demand lists of cities conforms to a pattern I have discovered while playing all the civs in a hot seat test game of MGE.

In this game, Trade was discovered by the Babylonians in 2250 BC, and was immediately shared all around, in order to reveal all supply and demand lists. In the 20 turns that followed, the way in which cities became eligible for a change to their supply and/or demand commodity lists adhered to a consistent pattern.

The pattern is best observed by making a table or graph, and putting all the cities on one axis and putting game turns along the other. The cities must be listed in the order in which they were created as the game was played. The city list should include every city from every civ in the game. Game turns just proceed in their natural sequence, and if “O’s” and “X’s” are used to represent each turn, a graph or table will result that looks like the following:

Game turns in order of occurrence
City01 OOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOO
City02 OOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOO
City03 OOOOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOO
City04 OOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOO
City05 OOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOO
City06 OOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOOOOOOO
City07 OOXOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOO
City08 OXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOO
City09 XOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOOOO
City10 OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOOOOO
City11 OOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOO
City12 OOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOO
City13 OOOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXO
City14 OOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOO
City15 OOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOOO
City16 OOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOO
City17 OOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOO

The “X’s” represent the turns when a city had some kind of change to its supply and/or demand list. Notice that cities do not always undergo a change when they are eligible to do so, BUT also notice that a city must always wait until a turn where their row intersects a diagonal where the other X’s always line up on. Another consistency I noticed was that an X appearing on one diagonal is always 16 turns and 16 cities away from its buddies on the next diagonal when you follow sideways along the turns and downwards through the cities, respectively. Notice that cities created 16 spaces apart may both undergo supply and/or demand changes on the same turn. Also note that once a change takes place, another will not occur for that city until at least 16 turns later. This actually happened in my test game many times, since I started observations with 30 cities when Trade was discovered, and 20 turns later had added 11 more. During this time there were 34 occurrences of changing supply or demand, spread out over four separate diagonal lines, all lines adhering to the 16 spaces of separation.

This is kind of like oedo’s OOOX thing with revolutions, but you can see that it has been disguised a little bit better, since there are gaps left along the diagonals where the X’s line up, but they sure DO line up like little ducks!

I am trying to figure out if there is a system to the gaps now, as they may be part of a larger pattern that may emerge as the game progresses. At this point, I have just delivered my first caravan, with five more deliveries coming pretty soon, and I’m anxious to see how active trading will interact with the consistent underlying pattern I have seen so far governing supply and demand changes.

I will try to repeat the pattern below with the "X's" in boldface. This may not work.

Game turns in order of occurrence
City01 OOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOO
City02 OOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOO
City03 OOOOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOO
City04 OOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOO
City05 OOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOO
City06 OOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOOOOOOO
City07 OOXOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOO
City08 OXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOO
City09 XOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOOOO
City10 OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOOOOOOOOOOOOOO
City11 OOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOO
City12 OOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOO
City13 OOOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXO
City14 OOOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOO
City15 OOOOOOOOOOXOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOXOOO
City16 OOOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOO
City17 OOOOOOOOXOOOOOOOOOOOOOOOXOOOOOOOOOOOOOOOXOOOOO

(edited to fix typo noticed by samson in his post. In the origianl city list, city12 was accidentally omitted)

[DrSpike]

Bloody hell..........looks like 'solo' trading can begin.

[Space05us]

once you think Civ2 has been figured out someone has to come along and prove otherwise.

[samson]

Solo,

Mathematically, the relationship you describe is:

RemainderOf( (TurnNumber + CityNumber) / 16) = N

The value of N could be determined by knowing what year the first 'X' in your chart occurred.

It is possible this is merely part of a more complex algorithm for determining when supply and demand changes occur, with other factors masked by constant conditions in your test game. In any event, this is an important discovery.

One explanation for the missing X's is that the actual commodities for new supply/demand are chosen randomly from the 16 available types. For instance, if one new commodity is randomly selected from 16, there is a 3-in-16 chance that it will be the same as one of the current supplied commodities. Thus, we would expect to see no change in 3 out of 16 cases. This is roughly the incidence of missing X's your data shows. I count 10 missing X's out of 49 expected changes. That's quite close to 3-in-16. A larger data sample might be even closer.

Note: when I use the term "random" above, I do not mean that a restart will produce different results. That only happens when a random function uses a seed which is not restored by the restart. If the seed in the commodity re-supply algorithm is some factor which is saved, the algorithm can result in a consistent but still 'random' selection.

By the way, your charts are missing 'City12'. Typo or did something happen to that city? Which brings up the question of destroyed cities. When a city is destroyed, are all cities assigned a new number by shuffling them up the list? If so, then cities could shift places in the ordering of supply changes.

Good work. A piece of a puzzle has been found.

[solo]

samson,

The missing city12 is indeed, a typo, which I fixed.

The list presented above was just a hypothetical example, used to illustrate the pattern. I'm sorry if this misled you a bit. So far, there have been 11 missing "X's" in my actual test, which is about 1/3 of the 34 "X's" actually appearing, so far. If you would like, I can post the actual list, which continues downwards now for 40 cities.

I have also wondered what would happen if a city is destroyed, and may do this in the game soon to see if the list is re-shuffled.

Since I am keeping an entire record of the game details, this also includes the state of all of the commodity supply and demand lists shown by the trade advisor. It was from the demand lists, especially the one for dye, (at this state in the game, almost every city demands dye), that I noticed that cities were listed in the order of founding. When cities are added to or dropped from these demand lists, the ordering of cities on these lists always reflect their order of appearance into the game. I had to ask myself why does the game bother to do this, and the answer led to my discovery.

Anyways, while maintaining these lists, I have noticed that certain trends exist for certain commodities, i.e. some are gaining cities that host them while others are losing particpating cities. It may be that if all of a city's particular commodities are currently on the upswing, then no changes are made to the city's supply or demand lists. However, your random theory is another highly plausible explanation. I'm afraid more data is needed before attempts can be made to explain the gaps. I will post a summary of these lists, so far, if you are interested.

The gaps must surely be intentional, though, because if cities DID change supply every 16 turns, this would have become obvious to all of us long ago. I also expect that other factors come into play, once trading has commenced, instaed of always having just the 16 turn waiting periods currently enforced in my test game.

However, it was kind of exciting to discover this underlying relationship, and to see that none of the X's observed so far have tresspassed into the wasteland of all those surrounding "O's".

[samson]

Solo,

Yes, post the full list of X's and O's.

Another question. What happens when not all civs have Trade? Does the 16-turn pattern still include all cities or only the cities of Trade-capable civs?

I assume in your game you haven't made terrain changes. One thing I have observed several times in real game situations is that mining a grassland square into forest can produce a supply change on the turn after the transformation is complete. Usually, the new supplied commodity is Hides. I have tried changing the rate of transformation by adding and subtracting settler/engineers and find that the supply change always occurs when the transform is complete, not on a particular date. So terrain may be another factor.

[La Fayette]

solo...
This is no longer a research lab.
This is plain surgery.
Sid Meier torn into small pieces.
But it doesn't hurt: your hospital has been granted much finer narcotics than the Russian Special Forces.
...just one more turn...just one more change in commodity supply... long live civ .

[solo]

Thanks mon ami, La Fayette.

Okay, Samson, here is the real list. The first year was 2250, when Trade was discovered and shared all around. About 3/4 of the way through, is 1500, a unique year where all trade took a rest, without any X’s. This was the same year all civs were asked to check with their advisors. The last year is 1200. Cities will be listed on the right so as not to spoil the alignment of the X’s on the list. One note is that Hamburg had two commodities exchange positions on its demand list in 1650, so maybe that spot deserves an X. For now I mark it with a ?

(Read dates vertically. All years are BC)

2222221111111111111111
2211009988776655443322
5050505050505050505050
0000000000000000000000

OOOOOOOOOOOOXOOOOOOOOO Delhi
OOOOOOOOOOOXOOOOOOOOOO Berlin
OOOOOOOOOOXOOOOOOOOOOO Leipzig
OOOOOOOOOXOOOOOOOOOOOO Rome
OOOOOOOOXOOOOOOOOOOOOO Washington
OOOOOOOOOOOOOOOOOOOOOO Athens
OOOOOOOOOOOOOOOOOOOOOO Thebes
OOOOOOOOOOOOOOOOOOOOOX Memphis
OOOOXOOOOOOOOOOOOOOOXO New York
OOOXOOOOOOOOOOOOOOOXOO Babylon
OOXOOOOOOOOOOOOOOOXOOO Bombay
OXOOOOOOOOOOOOOOOXOOOO Veii
OOOOOOOOOOOOOOOOOOOOOO Sparta
OOOOOOOOOOOOOOOOOOOOOO Ur
OOOOOOOOOOOOOOXOOOOOOO Nineveh
OOOOOOOOOOOOOXOOOOOOOO Ashur
OOOOOOOOOOOO?OOOOOOOOO Hamburg
OOOOOOOOOOOOOOOOOOOOOO Heliopolis
OOOOOOOOOOOOOOOOOOOOOO Thermopylae
OOOOOOOOOXOOOOOOOOOOOO Madras
OOOOOOOOXOOOOOOOOOOOOO Ellipi
OOOOOOOXOOOOOOOOOOOOOO Boston
OOOOOOXOOOOOOOOOOOOOOO Antium
OOOOOXOOOOOOOOOOOOOOOO Konigsburg
OOOOXOOOOOOOOOOOOOOOOO Elephantine
OOOXOOOOOOOOOOOOOOOXOO Bangalore
OOXOOOOOOOOOOOOOOOOOOO Corinth
OXOOOOOOOOOOOOOOOOOOOO Frankfurt
XOOOOOOOOOOOOOOOXOOOOO Alexandria
OOOOOOOOOOOOOOOOOOOOOO Delphi
OOOOOOOOOOOOOOXOOOOOOO Akkad
OOOOOOOOOOOOOXOOOOOOOO Pi-Rameses
OOOOOOOOOOOOXOOOOOOOOO Calcutta
OOOOOOOOOOOXOOOOOOOOOO Uruk
OOOOOOOOOOXOOOOOOOOOOO Pharsalos
OOOOOOOOOOOOOOOOOOOOOO Cumae
OOOOOOOOOOOOOOOOOOOOOO Philadelphia
OOOOOOOOOOOOOOOOOOOOOO Knossus
OOOOOOOOOOOOOOOOOOOOOO Munich
OOOOOOOOOOOOOOOOOOOOOX Argos

Some interesting notes on cities where I happened to finish a build on the turn they might have earned an X, or actually did (In each case I exercised the zoom to city option):

1900 Athens’ temple showed a false change on the demand list
1850 Ellipi settler showed a false supply list before the one with the real changes
1750 Leipzig temple showed the same changes before and after the zoom
1650 Hamburg temple showed false demand list followed by the exchange of position of 2 items

NO changes were observed at all in these lists during ALL other zooms made for builds in the O years. So maybe completing a build on a zoom year can affect these lists. It is worth making a few tests for this by going back to saved games and delaying builds.

Some other notes:

1) 12 cities still have not shown any changes, but some of these cities are fairly new.
2) So far, 6 cities have changed their lists twice, but the second change for each was only among the turns from 1450 until 1250. During these turns, none of the other cities had any changes. Remember that 1450 followed 1500, where no changes happened at all, so I believe that date is significant.
3) The last 3 cities on the list were founded after 1500, and this event is probably the cause of the resumption of the first-time changes in 1200 for Argos and Memphis. 1200 was the last date played to so far. To complicate things just a little more, the first caravan delivery of the game was made in 1200, too.
4) The first two caravans built in the game arrived in the year 1600.


As for terrain changes, I have only made a few roads so far to connect my cities. No mining or irrigation yet. I believe that terrain changes DO have an immediate effect, since I also believe that the choices for commodity distribution among cities are at least partly due to surrounding terrain. I also believe that specials play an important role in these assignments, too, as I have often noticed that clusters of silk producing cities have a silk special in the neighborhood, and have noticed this kind of behavior with other commodities, too. I’m also pretty sure that commodity selection is tied very closely to one’s level of technology, which is already especially noticeable when dealing with coal, oil or uranium. To test the effect of terrain, it might be time to bring out the map editor, and see what can be surmised from cities founded on specially crafted city locales, but this is another big project.


Finally, as for the effect of the knowledge of Trade, my personal hunch is that all these changes are occurring before anyone knows about Trade, and that knowledge of the tech just reveals what has been going on. However, my hunches are often totally wrong, and this is easy enough to check since I have made a save of the game on every turn. All I have to do is go back to the save made previous to sharing Trade, and hog it instead, and continue making turns as before. The reason for my hunch is that when I have learned Trade, the demands of all cities I know about are instantly revealed. Also I have also seen an AI’s city change its demand just before delivering a demanded cargo too many times not to forget about it! If my recollection is correct, these deliveries were often attempted before the AI in question had the knowledge of Trade. In any event, I will go back and test this out.

I think I will also go back and rush a settler to cause a city to disband, just to see how the vacancy on the city list is dealt with.

That’s it for now. The more I get into this test, the more interesting things get.

[Xin Yu]

Good finding! When the commodities in a city don't change on a designed turn, it may just be that they changed to themselves.

[samson]

Thanks for the additional info, Solo.

I guess a question I have now, is whether the 16-turn phenomenon is a 'cause' or 'trigger' event. Does the game attempt to change a city's supply/demand every 16 turns or is it merely checking every 16 turns to see if other factors have changed and then making the changes visible? How can we test this?

As for terrain and resource specials. I did some testing in Cheat Mode with edited maps a while back and saw definite and immediate effects on suppy/demand from terrain changes. I agree that specials are important in determing the what commodities are suppied. Although I saw many examples of change, and could even predict changes after time, I have yet to discern a governing principle. This is tough problem.

[solo]

Xin Yu,

I hadn't thought of your idea, but I like it! It may explain some of the gaps!

Observe Hamburg, where two commodities on the demand list apparently "swapped" positions:

before:

demands: dye,wine,beads

after:

demands: dye,beads,wine

Although there were not any commodity changes, a change certainly has occurred. Instead of a direct swap, I suspect that list was processed as follows:

item 1 - Dyes is processed first and the decision is made to leave it.

item 2 - Process wine next and decide to replace it with beads.

item 3 - Now process wine. It is already on the list, so it must be replaced, too. Just by coincidence, wine is replaced with beads.

Now if your theory is correct, dyes actually replaces itself, and the other two items are replaced by each other, i.e. a replacement of some kind always takes place.


Many times I have also noticed "shifts" in position for commodities when changes are made. For example,

Antium before:

demands: hides,spice,wine

Antium after:

demands: dye,hides,spice

What this suggests to me, is that processing may actually go like this:

item 1 - At this time Antium "wants" dye the most, so hides is replaced by dye.

item 2 - Hides are now the second favorite choice, so they replace spice.

itme 3 - Spice is now ranked #3 in preference, so it replaces wine in the third position.

Every 16 turns the relative desirability of commodities changes, perhaps due to the passage of time or due to intervening events. Then replacements are made to the supply and demand lists based on revised desirabilities. If not enough change in desirability has occurred, all three items on the list simply replace themselves.


Other examples from my test game, where a zoom to the city was made on turns where an improvement build coincided with a commodity changing turn, may provide clues about this process, too. I suspect the zoom reveals an intermediate step in the processing of the lists, before the completion of city processing at the beginning of each turn.


samson,

Just noticed your post. I had the same experience, when using cheat mode to change terrain. Terrain changes may be an independent way of changing supply and demand, resulting in immediate differences.

Intervening events over 16 turns?

That does not explain what happened to Argos, founded in 1300, with:

supplies: dye,coal,copper
demands: beads,hides,wool

Just two turns later:

supplies: coal, copper,salt
demands: dye,beads,hides

I can provide several other examples.

However, I have also discovered that dyes are used for some special purpose, since I have observed a very systematic accumulation of the demand for dyes in position #1 of the demand column.

More later, after a few tests.

[-Jrabbit]

Civ2 Strat Forum's latest WoW = solo.


I watch and read in awe...

[solo]

Replay Test #1 - What happens if Babylonians do not share Trade after discovering it in 2250 BC

Only demand lists for foreign cities could be monitored, by clicking on their cities or by checking with the trade advisor. Lists marked as duplicate are those that changed to the same commodities as were observed in the original game where Trade was shared with all. Otherwise it will just be noted if a change occurred or not in a city where a change might be expected. Due to the turn order, changes for all civs except for Rome, are only noticeable by the Babs the turn AFTER they actually happened.

2250 Maps shared with all, in order to locate all existing cities. All original demand lists are checked and they duplicate the lists shown after trade had been shared in the earlier game.

2200 Alexandria – demand list changes, Veii – duplicate changes

2150 Frankfurt – no changes

2100 Babylon – duplicate, Corinth – duplicate, Bombay – changes

2050 Bangalore – changes

2000 New York – changes, Elephantine – no changes

At this time Trade was given to just the Germans, after which Konigsberg came in as a duplicate.

Finally, all cities were given a final check. None of the ineligible cities had any demand list changes.

From this test, it can probably be concluded that the pattern is in effect even for cities of civs that do not know Trade yet, since most cities eligible for changes did change their lists. However, the knowledge of Trade has an effect on the specific changes (or lack of changes) for eligible cities.

[samson]

Solo,

2250BC is turn number 35. On this turn, city29 (Alexandra) changed and city13 (Sparta) should have changed in the pattern, but didn't. Plugging these numbers into my formula gives a value of 0 for 'N'. Thus:

RemainderOf( (TurnNumber + CityNumber) / 16) = 0.

The fact that the changes occur when the remainder is 0 suggests that this portion of the algorithm is distinct from other factors. And may well be a 'cause' of supply/demand changes.

I agree with you that it seems likely the 16-turn cycle is independent of how many civs have Trade, and possibly independent of the discovery of Trade at all.

Re: shifting of commodities. I've seen this both in test and real game cases. It's an important clue, I think.

[solo]

Replay test #2 - What happens to the city list when a city is destroyed

Below is the relevant part of the chart plotting city changes vs. time. The replay begins in the year 2150, which is the first year displayed in this mini-chart. At this time a settler was rushed in Konigsberg, a size 1, German city. Just for future reference, Konigsberg had the following commodity lists:

Supplies: hides,coal,beads
Demands: wool,silver,wine

On the next turn, 2100, the settler was built and Konigsberg was disbanded. At this point a save of the game was made, because I wanted to test several things.

OOXOOOOOOOOOOOOOOOXO New York
OXOOOOOOOOOOOOOOOXOO Babylon
XOOOOOOOOOOOOOOOXOOO Bombay
OOOOOOOOOOOOOOOXOOOO Veii
OOOOOOOOOOOOOOOOOOOO Sparta
OOOOOOOOOOOOOOOOOOOO Ur
OOOOOOOOOOOOXOOOOOOO Nineveh
OOOOOOOOOOOXOOOOOOOO Ashur
OOOOOOOOOO?OOOOOOOOO Hamburg
OOOOOOOOOOOOOOOOOOOO Heliopolis
OOOOOOOOOOOOOOOOOOOO Thermopylae
OOOOOOOXOOOOOOOOOOOO Madras
OOOOOOXOOOOOOOOOOOOO Ellipi
OOOOOXOOOOOOOOOOOOOO Boston
OOOOXOOOOOOOOOOOOOOO Antium
OOOXOOOOOOOOOOOOOOOO Konigsburg
OOXOOOOOOOOOOOOOOOOO Elephantine
OXOOOOOOOOOOOOOOOXOO Bangalore
XOOOOOOOOOOOOOOOOOOO Corinth
OOOOOOOOOOOOOOOOOOOO Frankfurt

Pass #1 – See if gap in city list left by Konigsberg is filled in by an existing city

2100 On the Indian turn, Bangalore duplicated the change that originally occurred for that city during this year, so it appears it remained in the same position.

2050 Babylon is checked, a duplicate change occurred on the previous turn which can be noticed now, and since it was founded earlier than Konigsberg, this is not a surprise. Elephantine also displays a duplicate change. If it had filled the gap left by Konigsberg, this change would have been postponed until expected during the next turn, but this did not happen. Finally, New York displays a duplicate change.

2000 No changes, because Konigsberg is gone. It’s former slot appears to be empty.

1950 Antium displays a duplicate change.

From this pass, we can probably conclude that when a city is destroyed, it leaves behind an empty slot in the chronological city list.

At this time, I decided to use the settler from disbanded Konigsberg to build a new German city, Munich. (not to be confused with the Munich appearing later in the original game). This city was built one hex away from where Konigsberg had been and displayed the following trade lists:

Supplies: hides,beads,coal
Demands: wool,cloth,wine

Notice how similar the commodities are to those in the Konigsberg list. The only difference is the cloth in place of silver on the demands list! This is good evidence that that surrounding terrain affects the selection of commodities for any given city. The other thing to note is that when I checked the trade advisor wine demand list, this new city, Munich was listed right in between Antium and Elephantine, which is where Konigsberg had been before.

So we might also conclude that when a gap in the chronological city list occurs due to the loss of a city, the next city that is founded is inserted into that gap. The remaining cities always stay in their original positions on this list.

Pass #2 – What happens if the settler produced by Konigsberg rebuilds a city right away on the same spot

2100 Munich is built right where Konigsberg used to be. Commodities displayed were identical to those that Konigsberg had before it was disbanded. More good evidence that terrain dictates original commodity selections. The trade advisor wine demand list is checked, and Munich is in between Antium and Elephantine, just where Konigsberg had been before. Again, we might conclude the gap has been filled.

During the next few turns, Bangalore, Elephantine, and New York showed duplicate changes, which was expected. In addition, during Germany’s 2000 turn, Munich’s commodity lists underwent a duplicate change, too, mirroring what had happened to Konigsberg in the original game.

Pass #3 - What happens if another civ builds a city after Konigsberg is disbanded

2100 An Egyptian settler builds Pi-Rameses, which has the following commodity lists:

Supplies: hides,dye,copper
Demands: beads,salt,wool

Not much similarity to the Konigsberg list. More evidence in favor of terrain dictated lists. However, when the trade advisor lists were checked, it appeared that Pi-Rameses had filled the slot left behind on the chronological city list left by Konigsberg.

2050 The German settler coming from Konigsberg builds Munich right where Konigsberg had been before. The commodity lists were identical to those of the original Konigsberg. Here again, terrain must be dictating these. When the trade advisor demand lists are checked, Munich is listed dead last, the expected position of a new city, when there are not any gaps to be filled.

2000 Pi-Rameses has a change in its commodities, which is expected, because now it holds the position in the chronological list originally held by Konigsberg, and 2000 would have been Konigsberg’s year for change, had it remained in the game. Commodities for Pi-Rameses changed:

Supplies: hides,copper,salt
Demands: dye,beads,wine

On the trade advisor wine demand list, Pi-Rameses was listed right in between Antium and Elephantine.

I guess the original question has been answered! In a nutshell: The gap left by a destroyed city in the chronological list is filled by the next new city that is built. Other cities maintain their original positions on the list.

samson,

yes, it looks like whenever N = 0 for any city, a change is likely. Thanks for the formula, which makes it easy to check for when any city is "due" for a change.

[-Jrabbit]

Outstanding work, solo!!!

Sure makes me wish the game offered duplicate chronology (4000bc = Turn 1, etc.) to make tracking this sort of thing a bit easier.

[William Keenan]

I’m also pretty sure that commodity selection is tied very closely to one’s level of technology, which is already especially noticeable when dealing with coal, oil or uranium. To test the effect of terrain, it might be time to bring out the map editor, and see what can be surmised from cities founded on specially crafted city locales, but this is another big project.

Discovering Industralization causes cities to supply oil. Building Superhyways causes cities to demand oil. Discovering Nuclear Fission causes cities to demand Uranium.

[Scouse Gits]

Originally posted by William Keenan
Discovering Industralization causes cities to supply oil.

Sorry...but that is incorrect. In a recent game I had an oil supply in one city with the discovery of trade...circa 2700BC !

------------------------

SG(2)

[-Jrabbit]

He specified that Superhighways (sic) cause Demand (not Supply) of oil. That's = Automobile, right?

[samson]

I confirm SG's observation. Oil is available as a supply commodity from the start, often found occuring cities with the oil resource or having a large number of desert squares.

In fact, I believe that commodities which have a corresponding resource (Gold, Silk, Spice, Oil, Coal, Wine and Gems) are frequently supplied by cities built near that resource.

[Elephant]

Congrats, Solo. You got the first leg of the "final frontier"...

I was suspecting the order of city starts had something to do with WHICH commodities were supplied, not WHEN they changed. I was looking at ContinentNumber too,rather than specific terrain. I had not been paying attention enough to changes due to terrain in the city radius. I'm going to have to start over again. Sigh.

I was looking at terrain issues but had not logged enough of that in my notes. I did get a few good maps with each civ on a separate island, versus all on the same continent. Seemed like it made a difference.

Practical matter: how will we know the order of settlement of AI cities? Track the commodity changes and work backward? The first seven are probably obvious, but after that...?

[solo]

First, a few comments about other posts:

When a new commodity is being chosen at this stage in the game to replace another on the demand list, there are probably only 6 to choose from, a limited supply. 5 out 16 are taken by the other commodities on the lists. (I have not yet noticed a city supplying and demanding the same commodity at once) 4 out of 16, coal, gold, oil and uranium, do not appear on early demand lists. A commodity replacing itself (if this happens) is one more chance out sixteen that can not be counted as a change. That only leaves 6 candidates to choose from.

-Jrabbit,

It’s not really necessary to keep track of all turn numbers, as long as you know the city numbers. They can be pieced together using the Trade Advisor demand lists. Once known, they never change. When a supply or demand change occurs, just note the city number and how far it lies from the particular city that interests you on the list.

Elephant,

Your use of different continents is another key ingredient, I think in the terrain generated lists. Keep going with that!

City order is easiest determined by the dye demand list, since all AI cities except the very latest will end up on that one. Use other demand lists provided by the Trade Advisor to find the exact positions of your own cities. Also, given the turn #, which can be known for sure, you can use Samson's formula to determine a city number when you notice a supply or demand change taking place.

Oil and terrain,

I have also seen oil early, but concur with William’s other observations.

I’d also bet a lot that the first supply and demand lists for each city are determined entirely by the surrounding terrain. I believe that subsequent lists are determined partly by the “dye phenomena” (discussed below), by the current commodity preferences, and also again by terrain, all of which vary during the course of the game.

Following is the latest test:


Test #3 – Some research about additional questions

1) Does this 16 turn pattern occur in other versions of the game?

My test game, where this 16 turn pattern was first observed, was in an MGE hot seat game without any AI civs. I wanted to see if the pattern could be observed in another game, so thanks to the start provide by SG, where the English began the game with Trade, this question and several others could easily be put to the test.

I used my 2.42 version of Civ II, rather than MGE, this start used a large map, rather than the standard one in my MGE game, and SG’s start was a single player game including AI opponents, rather than my MP test game. Enough difference, I would hope, for testing this question.

With Trade at the start, I was able to use the Trade Advisor supply and demand screens to monitor the demands for the AI capitals, as they were founded. These were checked every turn, for any changes. Added to the AI capitals, was my own, London, founded sixth. I founded York, which came in eighth a turn later, which filled the slot behind Delhi, city #7. No contact was made with any of the AI during this test.

The first change that occurred in the demand lists was for York in the year 3600 BC, exactly 8 turns after the start. Using Samson’s formula, it was encouraging to see that when York’s chronological position as city #8, was added to turn #8 (3600), the total was 16, which when divided by 16 yields a remainder of zero, the same as in my MGE test game. The next change was Delhi, city #7, during turn 3550 BC (turn #9), conforming to the zero remainder pattern. (Actually, this change could not be observed until 3500 BC, because the English have to wait a turn to see any changes taking place for the Indians).

The next change would be expected for London in 3500 BC, but nothing happened, but gaps in the pattern are to be expected. As long as cities stick to the pattern when they do change, things are fine. The next five turns resulted in changes for Beijing (city #5), Madrid (#4), Crewe (#3), Zimbabwe (#2), and Cardiff (#1), in that order with Cardiff’s change coming in 3250 (turn #15).

After this, no changes occurred until the pattern fell over this group of 8 cities again. On the second pass, Delhi had another change in 2750, London had its first change in 2700, and Beijing had another change in 2650, while gaps were observed for the other 5 cities. As the game continued through a few more 16 turn cycles, cities that changed did so in accordance with the pattern.

So, to answer the original question, it appears that the pattern does apply to different versions and ways of playing Civ II, and that the remainder N, as determined by Samson’s formula, will always be zero when a change is enabled by it.

(One side note, of interest, is that the year 3250, the first year that a change is possible for the first city founded in the game, coincides with the first spontaneous appearance of barbarians in the game, too. Anyone who has made tests with the map revealed, may have noticed these spontaneous barbarian “landings” also come in 16 turn cycles. Even though the turns this will happen are very predictable, the location of these appearances is randomized, making it unlikely for individual players to notice the 16 turn cycle while playing the game.)

2) Can supply and demand changes occur at times other than those predicted by the pattern?

Yes, the 16 turn cycle is only one factor governing changes in supply and demand. In my observations so far, which have been early in the game, without many events going on, cities have only been changing on “expected” turns. However, there are independent events that may enable supply and demand changes, too.

Samson has already pointed out that a change occurred for him when he made a terrain change, and that this change was tied to the turn that this event occurred. When he purposely delayed the event for a turn or two, the change in supply and demand was also delayed until the turn the terrain actually changed.

Using SG’s start in another test game, I spent my time building caravans and conducting trade between my two cities, London and York. For awhile, this trading had no effect on the 16 turn cycle governing changes, but finally, the delivery of a caravan from York to London resulted in the appearance of a new supply in York’s supply list. This happened two turns before York was “due” for a change. So I built another caravan using this new supply of gold and delivered it to London. No change! However, on the next turn York was due for a pattern change, one occurred, yielding a new supply of gems, and leading to a situation of alternating supply. During this whole time, nothing was happening to London’s supply and demand lists, although London was also building and using caravans.

Anyways, the question is answered. There are alternative ways of changing supply lists, rather than just waiting every 16 turns and hoping for a change. It appears that there may even be some underlying connection between “independent” events and the cycle, too. A lot more unraveling needs to be done, here!

3) Are there any causes to the gaps appearing in the pattern?

I do not have a definitive answer to this, but have discovered a few things that provide evidence that gaps are not a result of a randomized selection of supply and demand choices that happen to result in no visible changes.

a) More gaps were observed for cities belonging to civs that were isolated (i.e. had no contact with any other civ) and for civs that had not yet learned Trade. An earlier replay of my test game, where Trade was not shared around by the Babylonians, yielded more gaps in the pattern, than occurred in the original test. A consequence of sharing Trade was the initialization of contact with a number of the isolated civs, too. Another thing I did when sharing Trade was share maps, so more geographical knowledge may be another factor entering into this equation.

b) During my test, trying to answer question #1 above, I also kept track of all the demand lists of each civ. Of special interest was the demand for dye, because in my MGE test game, sooner or later dye had become fixed in position #1 every city’s demand list, the exceptions being the cities most recently added to the game. This was also accomplished for every new city, too, as soon as permitted by the 16 turn cycle. Why?

My test using SG’s start provided a clue. Of the 8 cities being observed, only York, one of my own, started out demanding dye. During York’s first change in 3600, dye was dropped from its demand list. Oh well, I thought, so much for the “everyone wants dye” theory! I continued observing the action with dye, though. The next 6 changes involved AI cities, all occurring during this first 16-turn cycle:

(Note: the ordering of these lists could not be determined using just the Trade Advisor)

Delhi demands wool, dye, wine
Beijing demands wool, beads, dye
Madrid demands cloth, dye, gems
Crewe demands beads, dye, gems
Zimbabwe demands hides, dye, wine
Cardiff demands hides, beads, dye

Dyes jumped onto the demand list of every AI capital! After this cycle, dyes were gone from the demand lists of my own cities. AI cities only began showing gaps after they started demanding dye! The fact that the human player is the only non-participant in this scheme, suggests more purpose than chance behind commodity change selections. Further evidence of this is provided by the display below, showing the demand for dye plotted vs. game turns in my MGE game, where an “X” means dyes are currently on the list:

XXXXXXXXXXXXXXXXXXXXXX Delhi
XXXXXXXXXXXXXXXXXXXXXX Berlin
XXXXXXXXXXXXXXXXXXXXXX Leipzig
OOOOOOOOOXXXXXXXXXXXXX Rome
XXXXXXXXXXXXXXXXXXXXXX Washington
XXXXXXXXXXXXXXXXXXXXXX Athens
XXXXXXXXXXXXXXXXXXXXXX Thebes
XXXXXXXXXXXXXXXXXXXXXX Memphis
XXXXXXXXXXXXXXXXXXXXXX New York
XXXXXXXXXXXXXXXXXXXXXX Babylon
XXXXXXXXXXXXXXXXXXXXXX Bombay
OXXXXXXXXXXXXXXXXXXXXX Veii
XXXXXXXXXXXXXXXXXXXXXX Sparta
XXXXXXXXXXXXXXXXXXXXXX Ur
XXXXXXXXXXXXXXXXXXXXXX Nineveh
XXXXXXXXXXXXXXXXXXXXXX Ashur
XXXXXXXXXXXXXXXXXXXXXX Hamburg
XXXXXXXXXXXXXXXXXXXXXX Heliopolis
XXXXXXXXXXXXXXXXXXXXXX Thermopylae
OOOOOOOOOXXXXXXXXXXXXX Madras
OOOOOOOOXXXXXXXXXXXXXX Ellipi
OOOOOOOXXXXXXXXXXXXXXX Boston
OOOOOOXXXXXXXXXXXXXXXX Antium
OOOOOXXXXXXXXXXXXXXXXX Konigsburg
OOOOXXXXXXXXXXXXXXXXXX Elephantine
OOOXXXXXXXXXXXXXXXXXXX Bangalore
OOXXXXXXXXXXXXXXXXXXXX Corinth
OXXXXXXXXXXXXXXXXXXXXX Frankfurt
XXXXXXXXXXXXXXXXXXXXXX Alexandria
XXXXXXXXXXXXXXXXXXXXXX Delphi
OOOOOOOOOOOOOOXXXXXXXX Akkad
OOOOOOOOOOOOOXXXXXXXXX Pi-Rameses
OOOOOOOOOOOOXXXXXXXXXX Calcutta
OOOOOOOOOOOXXXXXXXXXXX Uruk
OOOOOOOOOOXXXXXXXXXXXX Pharsalos
OOOOOOOOOOOOOOOOOOOOOO Cumae
OOOOOOOOOOOOOOOOOOOOOO Philadelphia
OOOOOOOOOOOOOOOOOOOOOO Knossus
OOOOOOOOOOOOOOOOOOOOOO Munich
OOOOOOOOOOOOOOOOOOOOOX Argos
OOOOOOOOOOOOOOOOOOOOXX Neapolis

(I'm sorry to see that O's are fatter than X's. But the pattern for dyes can still be ooobserved fairly well)

In this game there were not any AI. However the Romans, perhaps because they start the game as the “host”, have the only early cities not demanding dye, Rome and Veii, when my observations began. However, in this MP game, things were equalized later, as even the Romans succumbed to this craving for dyes. Come to think of it, when checking lists while playing Civ II, the dye demand list has always been very crowded.

The patterns on the dye list are undeniable. Other lists show a hint of being more random, but many of them still follow trends that continue for a long stretch of game turns. I believe that when supplies and demands change, these trends are more responsible for new choices than randomization.

[samson]

coal, gold, oil and uranium, do not appear on early demand lists.

Not true for Gold. In my 16AD, the Mongol capital demanded Gold right at first contact. The other three I agree with, I think demand for them is triggered by tech advances.

I have not yet noticed a city supplying and demanding the same commodity at once

This definitely happens, though possibly it is a late game phenomenon. This snap is from the post-Automobile period.

[solo]

Samson,

Thanks for those corrections.

I was hesitant to add gold to the list. It would have been more accurate to say this was true for gold during my test game. One game hardly establishes a happening as a general rule!

The other 3, coal, oil and uranium, also share something else in common, in that they are all used as fuels.

I stand corrected on dual supply and demand, and am again confounded by an exception to what seems to be more of a valid observation, made from the experience of playing many games!

[Straybow]

Is the city order is reflected accurately in the "Find City" command? As long as you have an embassy you should know all city names for that civ. Having all embassies then gives you a complete list in order.

In playing our recent succession game I noticed that a new city appeared in an odd place in the F1 city list. Most of the cities shown were founded early in the game, (eg, Hoover Sucks before 225 BC) except VotesForWomen, founded by popping a hut shortly after 1650. So why does it appear amongst cities that were built before 1500 BC?

I hadn't noticed new cities in other games ever appearing anywhere but the end of my F1 list. The game in focus is played on MGE, and I have only been MGEing for less than a year, so maybe it is a post-2.42 change made in coding?

[solo]

Straybow,

Yes, the order is the same when using the Find City option, as I have checked it with a game using the 2.42 version of Civ II. I would expect the MGE find city to work the same way.

As long as you have recently exchanged maps with all civs, the list should be complete, too, and would be the quickest way to determine the correct city order.

Thanks for suggesting this better idea of using find city to get the complete chronological city list.

As for your other question about a new city being inserted among the older ones, a possible explanation might be that one of the your cities was destroyed or captured, creating a vacancy on your personal city list that was filled by VotesForWomen.

[Scouse Gits]

solo - thanks for another good read! Dye does seem to dominate demand lists in some games ... but not in every game.

Two commodities which bring equal trade bonuses are Silk and Spice, yet the former is always more common than the latter. This raises the subject of major and minor commodities. 16 commodities are available but only half seem to be widely used. The following seem to be traded more frequently:
Hides, Beads, Salt, Dye, Wine, Silk, Gems and Oil with its demand coming in the later game.

-----------------------

SG(2)

[solo]

SG,

Thanks for that post, and for reminding me that some games do not feature so much activity in dyes, as I was almost ready to conclude that this may be a routine activity in the early part of each game.

I agree that those commodities on your list get most of the activity, too, and have got to wonder what it is that makes things turn out that way for the ones not tied to certain eras. If commodity selections are mostly tied to the type of surrounding terrain, it could be that our natural tendency to avoid having many city tiles with “poor” terrain could be limiting the activity of commodities linked to inhospitable terrain.

When I provided information about dyes in my last post, I also mentioned that the other commodities seemed to be following trends of their own, although not as clearly defined as that of dyes.

Just to illustrate this, I will provide charts below of the changes in supply or demand for each commodity. A plus will indicate an addition of that commodity on a list, and a minus will indicate a commodity that was replaced. If either are in boldface type, this will mean there were either two additions or deletions on that game turn. Turns where no changes occurred will be marked with a dot and turns where both an addition and deletion occurred will be marked with b for both. This will probably look crummy, so be warned in advance! Here goes:

Changes on supply lists are followed by changes on demand lists for each commodity:

….+…+ +--.-….. hides -….-..--..--++.+.--.+
……….+…..- wool .++++-..-…..-…..-.-
.-…..-…….+…+++. beads ..---…+.++…..-…-
..+…..+…+.+……. cloth .--..+.-…-.b….+…
….-.-…..b……..+ salt ….+……………..
…-……….+..+…-- coal ………………….
…+….-…..-….-.. copper ..+……..+………..
..-………-……..- dye ++++++++++.++++……+
……+…….+.b….. wine .-..b--++---.--.-…..
.+……….-…+….- silk …………..-….+..
..+….+………..--.. silver ……………….+..
…………………. Spice ..--…..-……..+….
…-……-……..+.+ gold ………………….

Oil and uranium have not appeared yet. There you have it, for what it's worth. Perhaps there is enough evidence of trends to rule out randomization of changing supplies and demands. There really isn’t enough going on to try and detect a method at work behind it, either. Perhaps we can rely on Samson’s brainpower for figuring out this one, as I bet the solution to all of this is as tricky as his key civ discovery.

[samson]

Two commodities which bring equal trade bonuses are Silk and Spice, yet the former is always more common than the latter. This raises the subject of major and minor commodities. 16 commodities are available but only half seem to be widely used. The following seem to be traded more frequently:
Hides, Beads, Salt, Dye, Wine, Silk, Gems and Oil with its demand coming in the later game.

I think terrain is the key here. I believe it is one of the determinents of supply anyway. Cities are not randomly founded, locations with productive terrain are selected. Thus, commodities appearing with greater frequency may be those associated with the terrains more suitable for cities.

Perhaps a study should be done in which the frequency of commodites appearing in supply and demand lists (over hundreds of cities) is compared with the frequency of the various terrain types found within the city radii. A statistical correlation might prove insightful.

[Straybow]

SGs can confirm or correct me since it was on their turns that Votes4W was built. Some German cities were captured afterwards, but no Mongol or German cities were destroyed. The other civs would take some cheat menu to find out.