This one really looks impossible!
Here's how it goes: you push a small magic wand through a hole in a square tube, which blocks the opening in the tube. Anything trying to pass through the tube will be blocked by the wand. But then you drop a die into the tube- and it passes through the wand and out the other end of the tube!
This is a clever piece of magic equipment! Shows up well for a small group or classroom too!