How many balls?
The picture shows what happens when you put just one ball in the kaleidoscope of the tetrahedron. The 24 balls correspond to the 24 elements of the symmetry group of a regular tetrahedron.
You can see an analogous photo in the same kaleidoscope; or the photo of an analogous situation in a different kaleidoscope.
From the exhibition Simmetria, giochi di specchi - Symmetry, playing with mirrors.
The image belongs to the sections...:
The symmetry group of the tetrahedron (*332) (Symmetry)
In the yellow kaleidoscope (tetrahedron) (From the exhibitions of matematita)