Wednesday, 1 January 2014

Five curious and interesting mathematical objects

Here (in no particular order) are five of the interesting mathematical objects I have gathered over the years. These ones come from three continents and are made of ceramic, wood, plastic and metal.

Number One - Trench's Triple Initial

Triple Initial

The late Kevin Holmes sold wooden puzzles at Covent Garden for many years.  These bespoke "Triple Initials" are solid cubes out of which three interlocking letters are carved.  

Number Two - Three hares with only three ears between them

Three hares tile

David Singmaster has traced the history of this motif - sometimes called the "Tinners' Rabbits", and in the UK particularly associated with Cornwall - to its origins in the far East, whence it spread along the Silk Road.  

Number Three - a strange map of the UK

Jigsaw map of UK

This wooden jigsaw map of Great Britain and Ireland has the remarkable property that every piece is in the form of characters from Alice in Wonderland.  A map of the UK based on a favourite British book - a wonderful present from my sister Rosie from her time in Jakarta!

Number Four: A non-snail snail ball

Non-snail snail ball

What is a "non-snail snail ball"?  Well, a snail ball is a cleverly constructed ball which rolls down a slope extremely slowly, contrary to our expectations.  I got one at Village Games in Camden Market many years ago. For an explanation, see this article by Stan Wagon.  The non-snail version looks and feels identical but doesn't have the "snail" property.  Mine came from (from whom I have lifted the picture).

Number Five - Dr. Nim

Dr Nim

Dr. Nim is an amazing marble-powered machine from 1966 which plays perfectly a version of Nim's game. This was a wonderful Christmas present from Noel-Ann Bradshaw.


  1. The triple initial reminds me the cover of my aging copy of Hofstadter's book "Godel, Escher, Bach: An Eternal Golden Braid". This has a similar illustratuon of the letters E, G and B. See

  2. Yes - that is what I thought of the moment I first saw an example of the triple initial at Covent Garden. The maker was unaware of the Hofstadter book, which I think I showed to him at some point.