most of my code libraries are contained in two modules. blcairo, which is all rendering code. It's got the cairographics bindings. And bitlib, which is pretty much everything else, but knows nothing about rendering. The biggest part of that is probably geom, which has points, lines, circles, rectangles, polygons, all kinds of shapes - but only as models of shapes. blcairo knows how to render them all. This circle packing just returns lists of circles, which makes it very flexible.