KSEG is a Linux program for exploring Euclidean geometry. You create a 
construction, such as a triangle with a circumcenter, and then, as you
drag verteces of the triangle, you can see the circumcenter moving in
real time. KSEG was inspired by the Geometer's Sketchpad, but I have
plans to go beyond the functionality that it provides. 

WWW: http://www.mit.edu/~ibaran/kseg.html

- Kuang-che Wu
  kcwu@ck.tp.edu.tw