Magic and LEGO
This idea is based on a classic magic trick.
A beam made of standard LEGO bricks is placed inside a three compartments box. The beam is clearly visible through the three windows of each compartment. When sliding the central compartment, the beam seems to have been cut into three separated parts. Sliding back the central compartment, the three parts come back together and the beam is restored and removed from inside the magical box.
This prototype was made with the available bricks I had. It might be more convenient to use different bricks, of different colors for instance.
A video demonstration is watchable here :