KSEG is a free (GPL) interactive geometry software for exploring Euclidean geometry. It was created by Ilya Baran.It runs on Unix-based platforms, it also compiles and runs on Mac OS X and should run on anything that Qt supports, it was also ported to Microsoft Windows.KSEG is a tool designed to let you easily visualize dynamic properties of compass and straightedge construction and to make geometric exploration as fast and easy as possible.