Undulation \Un`du*la"tion\, n. [Cf. F. ondulation.]
1. The act of undulating; a waving motion or vibration; as, the undulations of a fluid, of water, or of air; the undulations of sound.
2. A wavy appearance or outline; waviness. --Evelyn.
3. A motion to and fro, up and down, or from side to side, in any fluid or elastic medium, propagated continuously among its particles.
This is my take on the famous green benches featured in the "Stunning Nikon" ads a few months ago. I had no idea where these were but as we were taking a bus tour of NYC we passed a Federal Plaza with some interesting colors and shapes. When I returned later I was pleasantly surprised to find these were the same benches!
See my comment below for the exact location or check the geotag.
View large - 'Undulations' On Black