"Yes ma'am, Roll-Oh get," the robot says, as it goes to the kitchen to prepare dinner, opening a can of food and blowing fire to a candle. Roll-Oh walks clumsily, suspiciously like a man in an uncomfortable costume. Nonetheless, it ably frees the domestic housewife of all her daily chores, at the simple press of a button. This was the promise of robotics, demonstrated in the 1940 short film "Leave it to Roll-Oh", presented at the New York World's Fair. Mechanical robotics already automate so much of our lives, the film argues, that it will be only a matter of time before we can expect personal, four-limbed metal people as ready-made servants: watering our plants, greeting our mailman, helping cook dinner.