The sombrero vueltiao is a counting system before it is a hat. Caña flecha is split into strips; half dry in the sun to a beige-white, half sit three or four days in black mud and are boiled with vija until they hold a brown-black that never quite becomes black. Plaited together, the two make a braid whose repeating figures — pintas — carry Zenú clans, animals and landmarks around the circuit.

Quality is counted in paired strands: fifteen at the coarse end, twenty-seven at the finest. This system takes the same measure. Everything is a band on a strict cell module, the black is a dye rather than an ink, and the surface stays matte — dried grass has no shine.