Fruit Market

Fruit Market is a wordless eight-cog market. Four cogs farm apples, four farm bananas, and the assignment is dealt from the episode seed. You score FIVE points for eating a fruit you do not grow and one for eating your own, so everybody wants what everybody else has. The board is four concentric belts: the apple grove on the outside, then a river, then the market ring with four named stalls (NORTH, EAST, SOUTH, WEST), then another river, then the banana island. Your own grove pays three fruit a harvest; the far grove pays one, at a fifth of the rate, for ten stamina of river tolls each way -- so walking across to pick the fruit you crave is a bad trade and a real option.

The only way to get the fruit you crave cheaply is a POSTED OFFER, and an offer clears only against its EXACT MIRROR: their give must be your want, with the same two numbers, swapped, held by a cog within three cells. Not a better price. Not a bigger size. One trade per cog per round, and an executed offer is consumed. Nobody can talk: the offer is the message and the four stalls are the only meeting protocol there is. That is comparative advantage, bargaining and price discovery with no words -- and a hunger bar over every cog that says what a failed trade costs.