The rotations of the dodecahedron
The green straw, laid between the mirrors that form an angle of 90°, shows the 6 rotation axes of order 2 of the octahedron (lines that go through the midpoints of two opposite edges); the red straw, laid between the mirrors that form an angle of 45°, shows the 3 rotation axes of order 4 of the octahedron (lines that go through opposite vertices). Then, the yellow straw, laid between the mirrors that form an angle of 60°, shows the 4 rotation axes of order 3 of the octahedron (lines that go through the centres of opposite faces).
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The image belongs to the sections...:
The symmetry group of the cube (*432) (Symmetry)
In the blue kaleidoscope (cube) (From the exhibitions of matematita)
Octahedron (3D geometry)
Further information:
http://specchi.mat.unimi.it
