The Aperiodical 

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Maths Object: Nobbly Wobbly

By Christian Lawson-Perfect. Posted May 14, 2016

My maths object this time is one of my dog’s favourite toys: the Nobbly Wobbly.

In the video, I said it was invented by a mathematician, but Dick Esterle’s bio normally goes “artist, architect, inventor”. I’ll leave it up to you to decide if Everyone’s a Mathematician.

It’s a particularly pleasing rubbery ball thing made of six interwoven loops in different colours, invented by Dick Esterle.

On Google+, various people told me the unexpected fact that the outer automorphism group of $S_6$ is hiding inside this dog toy.

I’ve also found this Celebration of Mind livestream starring Dick Esterle from 2013 talking about all sorts of mathematically-shaped toys, including the Nobbly Wobbly.

Maths Object: Correntator

By Christian Lawson-Perfect. Posted April 10, 2016

Here’s another one of my favourite maths objects: the Correntator. It’s a simple mechanical tool to add up amounts of money. I bought it for about a tenner (new money) at a market.

This video is extremely shonky. Blame my phone, which can’t bring itself to record for more than 250 seconds at a time.

More information about the Correntator.

Maths Objects: polyhedra

By Christian Lawson-Perfect. Posted March 4, 2016

Time for some more maths objects! This time I wanted to show you the various polyhedra I’ve got around my desk.

• The tetrahedron is made out of a paper plate, following the instructions on the brilliantly kooky wholemovement.
• The sonobe cube is a classic. Mine’s made out of Post-It notes.
• The swirly thing is made out of curler units. Here’s a nice lady explaining how to use them to make a few different polyhedra.
• The classic reference for the Post-It note dodecehadron is James Grime’s video instructions.
• Once you can make a dodecahedron, add some more maths by edge-colouring it. I followed Julia Collins’ 5-colouring. Or if you’re more adventurous and less colourblind, look at George Hart’s colourings page for some really sophisticated patterns.
• I can’t remember how I made the icosahedron. Can anyone remind me?
• Finally, I’ve shown off the enneahedron loads of times. I wrote about its creation a couple of years ago.

Maths Object: “Groups”, by Georges Papy

By Christian Lawson-Perfect. Posted February 20, 2016

I had the idea of doing short videos about mathematical objects I’ve got lying around. First up is a very unconventional group theory textbook.