This is a brief follow-on to my last post dealing with Henry Dudeney's Haberdasher's Puzzle, a classic geometric dissection of an equilateral triangle into four pieces that can be reassembled to form a square. The two origami versions of the puzzle by David Petty and Jeremy Shafer were based on an isosceles triangle rather than an equilateral one. Thanks to Greg N. Frederickson's book on the amazing work of Ernest Irving Freese I learned that in fact this is a more general f

The Haberdasher's Puzzle is a geometric dissection generally attributed to the English puzzle expert Henry Ernest Dudeney (1857-1930), in...

This is a brief update to my previous post on Aart van Breda . Since publishing the original post I've been informed by Michel Grand that...

Here's an unusual envelope fold that demonstrates a couple of mathematical points relating to triangles. Maths is not my strong suit, but...

As anyone who has been following this blog will probably have realised by now, I like books. Especially books on two of my favourite...

This post is about a traditional design for a folded Wallet or Purse that's at least 150 years old and appears in many of the classic old...