The Growing Pot

The centipede game as a story: a pot that doubles on every pass, and logic that says take it immediately.

Four pounds sits on the table, 3 on Ann's side. She can take her 3 and end it, or pass - each pass doubles the pot and hands the choice across to Ben. Six rounds, reaching 256 if everyone passes, and whoever takes gets the larger share. Both see the whole ladder up front. The story asks how far the pot actually gets. You lock in a guess, then step through the answer and breakdown.

Why quant interviews test this

Interviewers want the unravelling argument stated confidently, then the acknowledgment that observed play differs and why - a test of treating models as tools. The written solution is at /brain-teasers/centipede/solution.

The The Growing Pot guide covers how scoring works, the strategy that wins, a worked example and the mistakes most players make.

More Brain Teasers games

• Screwy Pirates - Five rational pirates vote on how to split 100 gold coins, and you work out the split by backward induction from a one-pirate crew up.
• Tiger and Sheep - A hundred rational tigers and one sheep on a magic island, where any tiger that eats becomes a sheep itself - solved by induction on parity.
• The Split Deal - The prisoner's dilemma played as a story: two thieves, separate rooms, and one offer each.
• Stag or Hare - The stag hunt as a story: two equilibria, and a choice that comes down to trust.
• One Offer, No Discussion - The ultimatum game as a story: one split of 100 pounds, one accept-or-reject, no negotiation.
• Two-Thirds of the Room - The Keynesian beauty contest as a story: pick the number closest to two-thirds of the room's average.
• All Brain Teasers practice
• Every game guide