Robots may be one of the greatest 21st-century inventions, but up until Oct. 28, you couldn’t purchase one to help out with daily household tasks, such as emptying the dishwasher or vacuuming your ...

It’s a bizarre sight: With a short burst of light, a sponge-shaped robot scoots across a tiled surface. Flipped on its back, it repeatedly twitches as if doing sit-ups. By tinkering with the light’s ...