You can fool around with this... OR YOU CAN DO AN EXPERIMENT!!! As you can see when you move the yellow dots, (draggable) the red ones find the midpoint of each line and thread a line through each midpoint. The shape in the middle of the lines will always create a parallelogram (and I MEAN always even if you cross it to make an old fashion timer shape.[just make sure not to make a line ! ;) ]). Also even if you overlap 2 vertices it makes the center look like a triangle that is missing a side (it's not one!) it's still a parallelogram just hiding the sides behind. you can even make an A (capital A) try to find out how an comment if you found out.
