By George Hart for the Museum of Mathematics

The icosahedron consists of twenty equilateral triangles, meeting five at each vertex. Here are two icosahedron constructions you can make from soda bottles. These were designed and built by Mario Marin, whose web site shows many creative ways to recycle household objects into polyhedral structures.

Pairs of cut bottles are joined here to make “double bottles” which are used as the thirty edges of an icosahedron. The twelve yellow “flowers” are cut from plastic sheet, with holes that are locked into place by screwing on the bottle tops.

This lamp construction is built around a cardboard icoshadron as its core. A hole in each of the twenty bottle tops allows wires to pass through to power the small light in each bottle.

**More:**

- Math Monday: Two-layer geodesic spheres
- Math Monday: What to make with golf balls?
- Math Monday: Knitted cellular automaton tea cosy
- Math Monday: Whittling links and knots
- Math Monday: Magnet constructions
- Math Monday: Hexagonal stick arrangements
- Math Monday: Paper plate geometry
- Math Monday: 3D Hilbert curve from plumbing supplies
- Math Monday: Math-play with your food
- Math Monday: Mathematical art in the lava
- Math Monday: Balloon polyhedra
- Math Monday: Sierpinski tetrahedron
- Math Monday: Skewer hyperboloid
- Math Monday: Morton Bradley sculpture
- Math Monday: Tetraxis puzzle
- Math Monday: Giant burr puzzles
- Math Monday: Fractal polyhedra clusters
- Math Monday: Giant SOMA puzzle
- Math Monday: Tie your bagel in a knot!
- Math Monday: Playing card constructions
- Introducing “Math Monday”