> I need to pack circles into a partial annulus ie part of a larger circle > bounded by two radii and angles of say 18 & 90.
You might take a look at Descartes Circle Theorem .... http://en.wikipedia.org/wiki/Descartes'_theorem Blub from google search .... In geometry, Descartes' theorem states that for every four kissing, or mutually tangent, circles, the radii of the circles satisfy a certain quadratic equation. By solving this equation, one can construct a fourth circle tangent to three given, mutually tangent circles. There is a screen saver in Debian Linux named Apollonian that uses this algorihm packing smaller circles into a larger circle .... The C source code for this screen saver is available under Debian .... -- Stanley C. Kitching Human Being Phoenix, Arizona -- https://mail.python.org/mailman/listinfo/python-list