For example, say you start with the labels 2, 5, 3, and 7 on the corners of your square like this.
2 5 7 3Your next square would then be
3 2 4 5where you place the differences in order as you take them around the first square (remember to take the positive differences). It does not matter what vertex you start with each time.
Now continue to make new squares in succession until you reach "the end". Try some different starting numbers. Amazing, huh? Prove that this always happens. What about polygons with a different number of sides? Try the triangle (1,1,0). Try 5, 6, and 7 sides, then try 8. Pretty amazing, huh?
Click here for Maple code to play the corner game.