Am I missing some sort of mathematical simplicity in the elliptical arc specification, because it looks like an absolute mess; surely there must be some mechanism that allows you to specify an elliptical arc between two points using tangent definitions, bezier-style. As it is, there's a real mess there where rotating the end point around the start point, you have to rotate the elliptical axis in the opposite direction to maintain the same curve.<p>It looks like its one optimal scenario is in creating a rounded corner, which I guess is the common use case - but the unpredictability of how the curve changes if you move the end points without adjusting the corner radii seems to be a significant downside.