This may sound like a fancy title, but it just means figures with flat sides and a hole in the middle! Continue reading Toroidal polyhedra

# Tag Archives: polyhedra

# Solids from regular sides

In this session we asked what solids can be made using regular polygons as sides. We investigated this almost entirely by playing around with snap-together polygons. And thanks to our campus 3d printer, we got to handle some of the more obscure shapes too. Continue reading Solids from regular sides

# Origami and geometry

A Platonic solid is a polyhedron with the same regular polygon on every side, and also the same number of sides at every vertex. The cube is the most well-known example, and the tetrahedron (pyramid with a triangular base) is another one. In fact, there are only five such figures possible! The other three are called the octahedron (8 sides), dodecahedron (12 sides), and icosahedron (20 sides).

How could these more obscure figures have been discovered in the first place? And how can we know for sure that there aren’t any more examples? We used origami paper to ponder these questions hands-on in this session, which was delivered by our special guest Paul Ellis of Manhattanville College and the Westchester Area Math Circle. Continue reading Origami and geometry