TotallyUnrelatedMathQuestions

Thought I'd pay a little visit back to the RoboWiki in an unashamed attempt to recruit some help for a little project I have going. It's a little hard to explain the problem, but I think I'm up to the task. Say you have a rectangular piece of elastic with a dot on it, and you stretch the four corners of the rectangle out different directions. Given the coordinates of the 4 corners and the point, I need to figure the coordinates of the point when the rectangle is unstretched. Any ideas? --Simonton