Sofía Táboas threw a stone into a lake. She then rowed a tiny boat to where the stone had landed and sunk, placing a buoy there to mark the spot; she threw a second stone and again directed the boat to where it landed. She repeated this sequence, five throws altogether, on one of the lakes in the emblematic and historical Chapultepec Park, the largest park in Mexico City.

Using a simple yet revealing gesture, one we have probably all made at some point—whether skipping pebbles across water, throwing coins into a fountain to make a wish, or playing marbles on the pavement—Táboas traced a mental