Firing a mixture of balls from a specially-made bowling machine he found the white balls deviated from a straight path much more than the red ones.

BBC: Does the white ball behave differently?

Clearing a path to the market soon will be the Winbot 7, a compact machine billed by manufacturer Ecovacs Robotics as the first full-service window-washing robot.

WSJ: Window-Washing Robots Rise; Humans Balk