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The Game Theory of Everythingsee the game you are already in
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The words people actually use at work and in the news.

20 shapes

The twenty

almost everything turns out to be one of these

Each one comes with how it feels from inside, who usually gets left off the player list, where it lands if nobody moves, what actually changes it — and the near neighbour people mistake it for, with the single question that tells them apart.

Two identical rooms divided by one solid wall, a seated figure in each, neither able to see the other.01
The Prisoner's DilemmaMutual cooperation beats mutual defection, but defecting is the better move whatever the other side does.
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Two cars stopped nose to nose on a pale road across a dark plain, their grilles facing each other across a small gap, a driver visible in the left one.02
ChickenTwo equilibria, both lopsided: one side concedes and the other does not. No dominant move.
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Two hunters crouched at opposite edges of a clearing, both watching one stag between them, with a hare near each of them.03
The Stag HuntMutual cooperation is the best outcome for everyone, but it is risky — and the safe option is available unilaterally.
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Two figures approaching each other on a wide pavement, both stepping the same way at the same moment.04
Pure CoordinationMultiple equilibria, no conflict of interest — the whole problem is agreeing which one.
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A public fountain in a paved square ringed by evenly spaced figures, most carrying a pale bucket and several carrying nothing.05
Public Goods and the Free RiderA non-excludable, non-rival good: contribution is privately costly and the return is shared, so it is underprovided.
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A wide open pasture with a scattered herd grazing across it, the near ground worn pale and bare, one small figure standing at the left edge.06
The CommonsA rival but non-excludable resource: each user's extraction imposes a cost spread across all users.
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A long strip of twelve equal cells, each holding a pale circle or a solid square like a ledger of past moves, with an arrow looping from the last cell back to the first.07
The Repeated GameRepetition creates a future cost to defecting today, which can make cooperation individually rational without changing anyone's character.
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A large beam balance with its beam dead level, a pale disc in the left pan and a darker disc in the right, a figure standing in front of it looking up.08
Zero-SumA strictly competitive situation where one side's gain is exactly the other's loss.
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Two figures at a table exchanging two different objects, each holding out one and receiving another.09
Positive-SumAn interaction with genuine surplus: cooperation produces more total value than the parties began with.
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A plain slab on a table cut into two very unequal pieces, one figure pushing the smaller piece across and a second hand hovering above it.10
The UltimatumOne side proposes a split; the other can only accept or destroy the whole thing.
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A figure standing alone on a stone jetty beside a burning boat, facing inland towards a distant second figure.11
CommitmentRemoving your own option raises your payoff, because it changes what the other side's best response is.
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Two figures at a table, one pushing forward a heavy sealed weight while the other watches, an untouched sheet of paper between them.12
Costly SignallingA costly, observable action that reveals private information because faking it would not pay.
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Two figures facing each other across a table: one has an open wire-frame box in front of them, the other a solid closed one.13
Screening and Adverse SelectionHidden information before the deal. The uninformed side designs the offer so that different types choose differently.
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One figure at a desk handing a folded instruction to a second figure who is walking away with it towards a door.14
Principal and AgentA delegated task with unobservable effort and imperfectly aligned interests.
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A very long dark corridor seen head on, a seated figure leaning forward at each end, the ceiling lamps lit near them and dark in the middle.15
The War of AttritionA contest decided by endurance, in which waiting is costly to both sides and the cost accumulates.
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Two stacks of identical blocks facing each other, each one course higher than the other, both leaning.16
EscalationA sequence in which each response justifies the next, and no step is individually unreasonable.
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A row of identical closed containers on a bench with one figure choosing where to look and another watching from a distance.17
The Inspection GameA strictly competitive game with no pure equilibrium: the inspector wants to match, the evader wants to miss.
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Several raised hands around a covered lot, with one hand higher than the rest.18
Auctions and the Winner's CurseIn common-value auctions, winning is evidence you were the most optimistic — so the winner systematically overpays.
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A field of small dots gradually connecting into one dense cluster on the right and leaving a sparse scatter on the left.19
Network Effects and TippingA good whose value to each user rises with the number of users, producing self-reinforcing adoption and lock-in.
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Two figures on either side of a table with a single long strip between them and a marker resting somewhere near the middle.20
BargainingBoth parties do better with a deal than without one; the negotiation is over the division of that surplus.
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