Blocks of ice demonstrate levitated and directed motion

Resembling the Leidenfrost effect seen in rapidly boiling water droplets, a disk of ice becomes highly mobile due to a levitating layer of water between it and the smooth surface on which it rests and melts. The otherwise random rotation and translation (sliding) of the ice block can be directed by controlling the flow dynamics of the melted ice-turned-water close to the disk surface.

(via WSJ)