Code overlap

The aim here is to visualize the degree of overlap between all pairs of entries in the contest.

I have tried to quantify the overlap between any given pair of submissions. The pairwise overlap matrix is fairly trivial to compute but time-consuming, so I've included a low precision pairwise overlap matrix.
Heatmaps and graphs are used to visualize the results. Visualizing large networks is one area where I find Matlab lacking and need to resort to third-party tools. Perhaps we can see better network visualiztion tools in the future?