Components and Nets of Regular Polyhedra
This Demonstration shows the five regular solids (or Platonic solids), a rhombic dodecahedron, and a rhombic triacontahedron. You can see a (possibly truncated) pyramid with vertex at the center of the polyhedron and base that is a face of the polyhedron. You can also see the fundamental region of a triangular pyramid. You can use a net to construct certain kaleidoscopes with three, four, or five mirrors.
The photograph shows a kaleidoscope made using a net of the truncated fundamental region of the regular icosahedron. The net is printed and metallic foil is glued to it.
 C. Palmer. 27 Blue Dihedral Kaleidos [Video]. (Jun 2, 2016) www.youtube.com/watch?v=rE7IWQtccbM.
 J. Richter-Geberrt. Four Mirrors and a Rod—MathLapse [Video]. (Jun 2, 2016) www.youtube.com/watch?v=zTS9SN18E58.
 Roe Goodman's Home Page, Three-Dimensional Kaleidoscopes, http://www.math.rutgers.edu/~goodman/pub/monthly.pdf