What's a robot manicure really like? Quick, cheap, and guilt-inducing.

A robot gave me a manicure last week.

Let me stop you before you envision a bipedal humanoid carefully dipping a brush into a bottle and lacquering my nails. Instead, the experience felt more like inserting my hand into a 3D printer.

Cameras inside an oversized microwave-like purple box scanned each fingernail. Then a small...