CirclePack is software for creation, manipulation, analysis, and display of circle packings; it handles circle packings having from 4 to (current record) 5,000,000 circles. For more about this topic see ”Introduction to Circle Packing: the Theory of Discrete Analytic functions” by Ken Stephenson, Cambridge University Press, 2005 (ISBN 0521823560) and papers on my web page kens/