Two robotic arms—a fork in one hand, a knife in the other—flank a seated man, who sits in front of a table, with a piece of cake on a plate. A computerized voice announces each action: “Moving fork to food,” and “Retracting knife.” Partially paralyzed, the man makes subtle motions with his right and left fists at certain prompts, such as “select cut location,” so that the machine slices off a bite-sized piece. Now: “Moving food to mouth,” and another subtle gesture to align the fork with his mouth.