Science Woodworking
Math Monday: Mathematical Coffee Table

By George Hart for the Museum of Mathematics


If you make a coffee table that express a mathematical idea and place it right in the middle of your living room, that certainly makes a statement to all who visit that math is central in your life.

This looks like an ordinary square coffee table, but note the cuts and the three hinges.

The table instantly transforms into an equilateral triangle, which is handy if you don’t know how many people are coming over.

This bottom view shows the structure. The seven legs are positioned to support it in each corner, in both the square and triangle configuration. Greg Fredrickson describes how Jan de Koning constructed it for Joop Van Der Vaart, based on a suggestion of Howard Eves, that derives from the original 1903 dissection of Henry Dudeny.

See all of George Hart’s Math Monday columns

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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 man’s memoir,” called Borg Like Me.

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