The Suitesparse matrix collection
(formerly known as The University of florida sparse matrix collection)
Sproing und Wobble: A Barrier Hessian Matrix from Convex Quadratic Programming (2009). Force-directed graph visualization places a positive electrical charge on each node and a spring on each edge and then computes a low-energy state for the graph, revealing the elegant structure of the mathematical relationships within this symmetric positive definite sparse matrix.
Daisy Chain: Financial Portfolio Optimization (2009). Optimizing a financial portfolio leads to a graph with many branches, each depicting a possible future economic scenario. Which path will your portfolio take?
A Fishnet for Shallow Water Equations (2009) A computational fluid dynamics simulation of a shallow bay of water pretending to be a shimmering green fishnet.
Web Poppies (2009) You like a web page and I like it too. 512 people like 394,792 web pages, do you like them too?
One Fish, Two Fish (2009) A blue constraint matrix from a linear programming problem meets a reddish-orange frequency-domain circuit simulation matrix constructed via the harmonic-balance method, swimming alongside.