Jorge Heraud is in a California lettuce field, and he's about to lose his mind. It's a balmy, cloudless day in October 2014. Salinas Valley stretches out around him like a Hidden Valley Ranch commercial, its endless rows of emerald leaves pushing up through the black soil. Heraud has come here to test Potato, a robot you might call the agricultural equivalent of an Apple 1 prototype circa 1976. The machine is trying to thin baby lettuce plants so the hardiest ones have space to mature. If you're imagining a C-3PO-style