Click some input points, then hit update and you get the canonical pseudotriangulation. You may then click near the midpoint of an edge to highlight (drag to change the highlighted edge) and release to swap the edge.
I should clearly allow to add/delete points from existing pseudotriangulations, rather than starting over from scratch; the UI is a modifcation of one for convex hull demos.
Code by Jack Snoeyink, University of North Carolina at Chapel Hill Back to Jack's Computational Geometry Demo page.