Speculation: I generally build wonders in a single turn with caravans; usually one of the caravans comes from the city building the wonder. It could be that sending this (non-food) caravan back to its originating city somehow breaks the trade code, causing it to keep cranking out commodities when it normally couldn't.

If this is repeatable, it could have major implications for OCC...

The Repeated Commodity Trade Strategy I originally posted ../../Forum3/HTML/000231.html involves repeatedly sending soome arbitrary commodity to the same destination city. This allows you to develop huge amounts of science and cash using the one time trade bonus.

An obviously related question is whether you can get an origin city to repeatedly supply some arbitrary commodity. There are several circumstances in which this might be possible.
1. Rehomeing the caravan from its origin city to another city, such as your super science city, will allow the origin city to supply the commodity again. This does not work indefinately, but it certainly works for long enough (four or five times per city?) that you can make a huge amount of money on the deal.
2. The commodities supplied by a city change from time to time during the game. While nobody seems to know exactly what causes this, we do have some general ideas. ../../Forum3/HTML/000813.html If a city supplies different commodities during a game, then it could send out more than three caravans even without rehomeing. People have apparently used this in OCC games.
3. I seem to remember that some cities will continue to supply some commodity, even after they have three trade route. IIRC, the commodity they supply is invariably hides.

Are there other circumstances in which a city might continue to supply some commodity? Does using a commodity caravan to build a wonder change the commodities a city supplies? (I always use food caravans to build wonders. This makes it much easier to keep track of my trade caravans.) Is there any way to make a city supply somehting other than hides after it already has three trade routes?

The implications of finding a way to repeatedly supply a commodity go far beyond the application. Repeated supply + repeated demand = essentially infinite money and science in any type of game you are playing.

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"I fear that I shall die a Prince."
-Edward VII, Prince of Wales

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Destroy or be Destroyed.
Conquer or be Conquered.
Strategy overcomes any odds.
Hit first,fast,hit last.
I am not a warmonger, i am just aggressively forcefull.

icq 30200920

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Scouse Git[1]

Some things I'm wondering: does the receiving city's production/absence of a commodity that you demand for a reciprocal route have anything to do with the recurrance of the delivered commodity? And does this only occur after both cities have three trade routes. Does the commodities bonus nature impact its ability to recurr - seems like all of the infinite deliverables are low end products. I 'think' I have had multiple routes of the same commodity between two cities, but I might be wrong. I delivered hides for the second time from Gretzkyville to Babylon, I didn't get it as my third trade; which makes some sense since there was an identical trade route in place.