The square of a difference

A geometrical proof of the square of a difference identity. Dragging the rectangles to check the similitude of the areas
Drag the sliders to select m and n take values The orange squares areas are and The pink square area is Each green rectangle area is 1.- Drag the orange squares and put them together so that both points A coincide Both squares together are: 2.- Drag the green rectangle so that both points B coincide 3.- Drag the other rectangle so that both points C coincide The remaining orange area is: 4.- Compare it to the pink area