These blocks can now rotate and change transparency. The movie on the left plays, but you can rotate the block on the right and change its transparency by clicking and dragging the cursor in the direction of the arrows. You may have to drag the cursor up quite a bit to get the transparency to change.
For single-headed arrows, the change will occur when you move the cursor in the direction indicated, but the change can be reversed by moving the cursor in the opposite direction. If you click and drag diagonally, the block will rotate and change transparency at the same time.