A circle packing is a configuration of circles having a specified pattern of tangencies, as introduced by William Thurston in 1985. The topic can be enjoyed for... » 

A circle packing is a configuration of circles having a specified pattern of tangencies, as introduced by William Thurston in 1985. The topic can be enjoyed for the visual appeal of the packing images and the elegance of circle geometry, for the deep connections to classical topics.There are intriguing open problems throughout the book. «