Ester Dalvit

Snow crystals have an amazing variety of shapes, but their structure is always the same: they have the same symmetry of a regular hexagon. A single slice is enough to reconstruct the whole crystal, using only reflections (1, 2, 3, 4 or 6 reflections, drawn in red in the movie) or rotations (of 60° or multiples, drawn in yellow in the movie). In mathematical terms, we can say that the symmetry group of a snow crystal is dihedral of order 12. I realized this short movie for the Science Museum of Trento, Italy (http://www.muse.it), where it is currently displayed together with an exhibit inviting visitors to play with mirrors to understand reflections and symmetries.