The sourcecode is hosted on github (github.com/sake/cl-treemaps). Tarballs can also be found there, but to be more convenient, the latest version is asdf-installable.
ASDF-install package (obsolete) http://git.electrologic.org/downloads/cl-treemaps_0.1.tar.gz
This package does not implement the Treemapping method for displaying tree-structured data by using nested rectangles.
Topics: data structure