Last year, Alec Rivers, a recently minted computer science Ph.D. from MIT, had a problem. He and his co-founder Ilan Moyer had created a digitally augmented power tool and planned to sell it through their company. After drawing a shape in third-party graphics software, a would-be carpenter could push the tool over a piece of wood, plastic, or even brass. Using computer vision software, the tool would automatically adjust the path of the cutting bit to match the digital image, amending the line to within a hundredth of an inch. The team liked to think of it as "autocorrect for your hands." But the tool didn't look quite sharp enough for the consumer market, and had a funny name: Taktia.