[Discover] KML Circle Generator http://dev.bt23.org/keyhole/circlegen/
(kml googleearth maps circle) 
[Discover] "Zen Circles of Illumination" by Belinda Sweet http://zenpaintings.com/article-enso.htm (painting circle)
[Discover] kmlcircle - Google Code http://code.google.com/p/kmlcircle/ (google maps circle kml)
[Discover] Great-circle distance: Definition from Answers.com http://www.answers.com/topic/great-circle-distance (map arc circle math)
[Discover] "Zen Circles of Illumination" by Belinda Sweet http://zenpaintings.com/article-enso.htm (painting circle)
[Discover] kmlcircle - Google Code http://code.google.com/p/kmlcircle/ (google maps circle kml)
[Discover] Great-circle distance: Definition from Answers.com http://www.answers.com/topic/great-circle-distance (map arc circle math)