The different colored blocks magically rearrange inside the tube. An early example of this prop, with the blocks made of Bakelite, an early form of plastic. Constructed so that the extra block will be held inside the tube with a force-fit, somewhat similar to a Chop Cup; only tapping the tube on a hard surface (or your hand) will dislodge it to make the trick work. Mild wear, else in very good condition.
