The front board plots a simplified wheat market: the horizontal axis is quantity traded (kilotonnes/week), the vertical axis is price ($/tonne). The blue line is the demand curve, the orange line the supply curve. The glowing point where they cross is the market equilibrium — the price and quantity that clear the market. The lane behind it traces how that equilibrium price has evolved over recent weeks.
Demand: P = A_d − B_d·Q. Supply: P = A_s + B_s·Q, where B = slope / elasticity. Equilibrium: Q* = (A_d − A_s) / (B_d + B_s), P* = A_d − B_d·Q*.
Elasticity sets how flat or steep each curve is. High elasticity → a curve barely moves in price for a given shift, but quantity swings a lot; low elasticity (inelastic) → the opposite — small quantity change, big price swing. This is why staple grains, which are demand-inelastic, see sharp price spikes during supply shocks.
Drag the glowing handle on the demand line up/down to simulate an income or preference shift; drag the handle on the supply line to simulate a permanent change in production cost or farmland yield. Both re-solve the equilibrium live.
The three weather buttons inject a temporary supply shock that decays back to baseline over several seconds — drought and floods pull supply left (price up), a bumper harvest pushes it right (price down). Small ambient noise also drifts supply every tick, so the market is never perfectly still.