Icosahedron in mirrors

thingiverse

This model represents one-eighth of a standard icosahedron. It can fit snugly into the corner of three mirrors, each positioned at a right angle to the others. Since this model is cut precisely along its symmetry axes, the mirrors will reflect a complete icosahedron image. This setup makes it easy for teachers to demonstrate symmetry in a classroom setting. There's also an STL file available for creating a dodecahedron model, which isn't shown in these photographs.