The omni-polihedron is a composition of the 5 Platonic solids based on the fact that they can be “inscribed” one inside another in different ways. One can find references of these properties in the book “De divina proportione” by Luca Pacioli, illustrated by Leonardo Da Vinci, published in 1498.
The construction of this figure is very popular at schools and allows teachers to introduce the 5 platonic solids, study their main properties, proportions, lengths, areas, volumes, symmetries, etc.
One can learn how to make it in Neotrie in the Booklet of activities.
If you did this omnipolyhedron send us your link!