undulation

undulation \uhn-juh-LEY-shuhn, uhn-dyuh-, -duh-\, noun:

1. A regular rising and falling or movement to alternating sides; movement in waves.
2. A wavelike form, outline, or appearance.
3. One of a series of waves or wavelike segments.

Considering the difficulty of the golf course, the severe undulation of the greens, the magnitude of the event and the quality of the competition, Inkster ranked it as her greatest victory, particularly because she turned 42 last month.
-- Clifton Brown, "GOLF; One for the Ages, As Inkster Wins U.S. Open at 42", New York Times, July 8, 2004

Both works suggest depth; "Greenscreen" feels as if you could tumble into it, whereas "Mt. Shasta" depicts it via landscape. Even the hint at undulation achieved with subtle shifts in shadow echoes the mountain's shape.
-- Cate McQuaid, "An artist with breathtaking scope: Painter races from concept to caress", Boston Globe, January 17, 2008

Undulation is from Late Latin undula, "a small wave," diminutive of Latin unda, "wave."