Smiling a little, Moncayo shifted his weight from one foot to the other, until the whole surface began to undulate beneath him.

NEWYORKER: Reversal of Fortune

This signal causes the surface of the crystal to undulate.

ECONOMIST: MONITOR

Designers can type in descriptors such as "sharpness" or "acceleration" (which refers to a curve's severity) and watch as the lines of a sports car or tea kettle automatically undulate.

FORBES: Easy Designer