[Tex/LaTex] Drawing a partitioned set with TikZ

graphicstikz-pgf

I'd like to create a graphic of a set partitioned into subsets of various sizes/shapes/colors. (I'm trying to show a set partitioned by an equivalence relation into disjoint subsets, i.e., the equivalence classes).

I was hoping to find something on http://www.texample.net to give me an idea of a good method, but I'm having trouble finding any examples. Does anyone have any suggestions?

\begin{tikzpicture}