The relay final is twenty minutes away and the changing room under the stadium is chaos. Someone has shuffled every kit card, one for each baton, spike shoe, water bottle and race bib, and laid them face down along the bench. Pixel Usain Bolt cannot walk out of the tunnel until every card sits next to its twin, and the team calls the job Relay Recall.
Here speed pays twice. A pair found hot on the heels of the last one counts double and buys a couple of extra seconds, just like a clean baton handoff. Miss, and the cards flip back while the clock keeps ticking. Each sorted bench brings a bigger pile of kit, and when the time runs out the announcer calls the runners to the track. How many benches can pixel Usain clear first?
