Discrete curve shortening flow
Try clicking below to add points to form a closed polygon (you have to click at least twice before anything shows up), and then click the other buttons to make it do stuff. Once there are at least three points; the “normal vectors” at the vertices of the polygon are displayed. Then you can click the button below to move one timestep forward to simulate the motion of the polygon under the discrete curve shortening flow. When there are only two points remaining the flow degenerates, and when two points in the flow get two close we replace them with only one point; I guess in the mathematical case this doesn’t cause any problems but there are sure to be some small numerical ones (note the discontinuous motion of the normal vectors).
Note that this is still a work in progress so there are probably some bugs. If you find any I’d like to know.