Don Stewart wanted to visualize the dependencies involved in the Haskell Language Packages, but ran into problems with existing graphics and dependency tracking tools due to the sheer size of Haskell (approximately 1100 packages).  So he built his own tool called cabalgraph, and generated some truly impressive dependency graphs.

There’s a lot of Haskell code in the world now. 1125 packages on Hackage, made up of thousands of modules, with hundreds of thousands of import dependencies between them. Some of those packages have hundreds of modules. For fun, I wanted to visualise that module namespace. That is, in one image see all the Haskell modules I could potentially use: a panoramic view of the Haskell landscape.

via Visualising the Haskell Universe « Control.Monad.Writer.