Morphing squares

Author:
Jean David
Topic:
Square
Morphing one square to another : Let P and Q moving proportionally on D'B and B'D. When P goes from D' to B, the square C'D'AB' becomes ABCD. As there is a common vertex, the points O and O' describe the diagonal C'A and AC. When P is at the middle of D'B, Q is at the middle of B'D, O at the middle of C'A and O is at the middle of AC. Moins