'Collections of Fibonacci numbers' 'Collection of perfect numbers' 'Collection of prime numbers' 'Collection of …'
Then his eye drifted away.
Another cabinet contained a variety of 3-dimensional solids. Muko could see a neat little label under each one, and looking along the shelves he read:
'Prism' 'Cube' 'Pyramid' 'Tetrahedron' 'Octahedron'
'Dodecahedron'
Then, on another shelf, some extraordinary objects caught his eye. They were like the solids in being symmetrical