Math DIY – How to Make a Skewer Hyperboloid!

Here’s a great way for you to learn about hyperboloids, by learning to make one yourself!

(via make)

Very neat stuff indeed!  Seriously, this could be used for crafts and other neat projects even if you don’t care about the math.

This is a hyperboloid (also called a “hyperboloid of one sheet”). It is a smooth continuous surface that can be obtained by rotating a hyperbola around an axis. (Actually, this is just part of an infinite hyperboloid surface; the top and bottom circles are where I arbitrarily cut it off; a complete hyperboloid has no edges.) Surprisingly, it is a ruled surface, which means every point in it lies on a straight line that is embedded in the surface.