[processing port] dotlassie's Carousel

Ported from dotlassie's 200-character Carousel
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* Carousel by dotlassie, licensed under Creative Commons Attribution-Share Alike 3.0 license.
* Work: http://openprocessing.org/visuals/?visualID=4559
* License: http://creativecommons.org/licenses/by-sa/3.0/
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