By George Hart for the Museum of Mathematics


We’ve seen mathematical pencil constructions in past Math Mondays columns. (Why go to the hardware store to buy dowels with all those shiny pencils just sitting there in the office supply cabinet waiting for someone to make things with them?) Here’s a lovely new design by Cory Poole. It is a five-pointed star assembled from eighty pencils.

There are five identical 16-pencil units around a central axis. Two units are shown below, before assembling. Each has the form of a hyperbolic paraboloid based on a four-edge cycle from a regular tetrahedron.

If you’d like to make your own, Cory provides step-by-step construction instructions.

See all of George Hart’s Math Monday columns

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.

  • Cory Poole

    I call it “Standardized Testing And Reporting.” (STAR for short)

  • Michael Edlavitch

    Have you seen the 175 free online math games at Check them out

  • Tad Tiboni

    I always buy my office supplies online because the price is cheaper. ”

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