Find all your DIY electronics in the MakerShed. 3D Printing, Kits, Arduino, Raspberry Pi, Books & more!

By George Hart for the Museum of Mathematics

Math_Monday_banner02_600px.jpg

A complete graph is what mathematicians call a collection of items in which every pair is connected. If the items are spaced evenly around a circle and the connections are shown as straight lines, the lines form an attractive pattern of concentric circles.

math-mob-complete-graph.jpg

This is a complete graph with eleven vertices. We made it at Mathcamp 2010 using plastic surveyor’s tape. There is a simple algorithm for constructing it in which people stand in a circle, and pass the roll from one to the next while counting aloud, wrapping it around their left wrist at the proper intervals.

math-mob-parabola.jpg

A similar algorithm, executed by people standing in two straight lines, gives this large parabola. The construction steps for both of these figures can be seen in the additional photos here.

More:
See all of George’s Math Monday columns

Gareth Branwyn

Gareth Branwyn is a freelancer writer and the former Editorial Director of Maker Media. He is the author or editor of a dozen books on technology, DIY, and geek culture, including the first book about the web (Mosaic Quick Tour) and the Absolute Beginner’s Guide to Building Robots. He is currently working on a best-of collection of his writing, called Borg Like Me.


Related
blog comments powered by Disqus

Featured Products from the MakerShed

Follow

Get every new post delivered to your Inbox.

Join 25,493 other followers