Classic "Cosine Surface"

 From:  bemfarmer
This is a quick and simple formula modification of the pillow script modification of Michaels LineWeb script.
Included is a "Half" version, which restricts the range of v curve to 0 - pi. Preliminary attempts to add a selection button for "full" and "half" were unsuccessful,
due to poor understanding of htm. I'm sure it is actually very simple...
Don't know what this surface is good for...