Skewer hyperboloid

By George Hart for the Museum of Mathematics

Thirty two shish kabob skewers and 176 small rubber bands are all it takes to make a beautiful hyperbolid of revolution. This is an example of what is called a “ruled surface,” meaning even though it is curved, it is made of straight lines.


Below is the same object seen from the top. Make one of your own following the instructions here, but be careful not to skewer yourself!



Gareth Branwyn

Gareth Branwyn

Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy person’s memoir,” called Borg Like Me.


    I just noticed there were no comments here so I want to leave one to make sure you know there’s interest. The bagel one kept me occupied with bagels, whiteboards and blog posts for weeks.

  • Gareth Branwyn

    Hey David, thanks so much for that. I was pretty sure this column was popular, from the traffic, the retweets, the in-person compliments I’ve gotten, but it’s nice to see it here. I’m really liking them too. Kudos to George Hart! There are some really nifty ones coming up, too.