At first, peas served as particles in Ernesto Altshuler's experiment. A mechanical dispenser would drop the chicharos one by one into the space between two glass plates, forming a tidy two-dimensional approximation of a sandpile. Lattice structure appeared, then vanished, as the pile self-organized and went critical—avalanche! But Havana's insects soon found the peas in Altshuler's physics lab. "I began to have too many degrees of freedom," he recalled with a smile. For a physicist working under the harsh economic conditions of Cuba in the early 1990s, options were few. Yet Altshuler's solution came as a byproduct of the crisis: Because of fuel shortages, the country had begun importing Chinese bicycles, and ball bearings were available in abundance. Thus the peas have been replaced by steel beads, but Altshuler and his students still call their machine the chicharotron.
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