title: How to use igraph vertex.shape functionality
body: <p>Has anyone used igraph's vertex.shape functionality?  This <a href="http://cneurocvs.rmki.kfki.hu/igraph/doc/R/igraph.vertex.shapes.html" rel="noreferrer">http://cneurocvs.rmki.kfki.hu/igraph/doc/R/igraph.vertex.shapes.html</a> was promising but I could not understand.  Does anyone have an example of working code?</p>