A fisher and a rice farmer share an Edgeworth box. He starts in one corner with nearly all the fish; she starts in the other with nearly all the rice. The shaded lens between their indifference curves holds every trade both would accept — and people, as it happens, grow attached to what they hold. Choose your seat at the market.
The Auctioneer
Call a price. Tap in the box to aim — the line through the endowment ω is your price — then tap the chip (or press Enter) to call it. Or type a price.
Read the market. Each trader picks their favourite point on your line — the red and blue dots. The Auctioneer’s Desk shows the excess demands and the distance to clearing.
Hurry. Each failed call is a day; overnight the traders grow attached to what they hold. The curves stiffen, the lens melts, the clearing price drifts. Get the distance below 1½% of the total stock before the lens closes — and beat Walras’s clerk.
Walras’s clerk starts at the box’s diagonal and mechanically nudges the price of whichever good is over-demanded, shortening his stride when he overshoots — tâtonner, to grope. Some markets die on him too.
The Fisher
Choose your attachment. The slider sets θ, how much you let yourself cling to your fish. Solid red is who you are; dashed red is who you commit to be at market.
Mind the farmer. Her attachment to her rice is her temperament, drawn by nature — the faint blue fan shows who she might turn out to be.
Go to market. A perfect auctioneer clears it instantly at the price your two masks imply. You are scored on your true tastes — attachment tilts the price your way, but too much strangles the trade. Five seasons.
After each season you learn her temperament and what your best attachment would have been against it. The score is the share of the truly attainable gain you captured.