Have the Courage
In group theory, a mathematical discipline, one deals with objects that can be transformed in a certain way so that every transformation is reversible. A prominent example of this is the Rubik’s Cube.
In this exhibit, loose plastic pieces are initially arranged so that the words Hab den Mut can be read on them. With the flat of your hand, you can now (carefully!) turn each of the four round parts of the puzzle and really mix it up.
Adjusting it so that the original text is visible again is a bit of a challenge.