You must be logged in and verified to contact the designer.
Five iterations of an 3D apollonian sphere packing: http://en.wikipedia.org/wiki/Apollonian_sphere_packing.
The starting point consists of the four red spheres and one big bounding sphere which is not shown: the 0th iteration. At each new iteration all spheres that are tangent to four spheres of the previous iteration are added. Each iteration has a different color.
Small version of https://www.shapeways.com/model/2994442/