Sphericon

A while back I got a copy of Ian Stewarts "Cows in the Maze" to review, and did.

Today I was glancing through the links for one of the chapters, "Cone with a Twist", which describes a shape called a sphericon. If you make two equal cones with a 90^o angles at the vertices and glue the two bases together then a cross-section cut through the two vertices forms a square, you can slice the shape with a plane through the two vertices, then rotate one 90^o and reconnect them and the shape is called a sphericon.

It is sort of a Mobius Strip in 3d since it has one continuous surface...and it rolls with a wobbly gate that makes it fascinating.. See below.

If you want to make one of your own (or many) a nice net for the shape is found here.

The fun really starts when there is more than one.... This site helps you to see how they can roll around each other.