Given that it’s conventional to give objects to other people around this time of year, we thought we’d collect together some suggestions for things we think you, a mathematically interested person, might like to buy for your mathematical friends (or add to your list before you send it off to Santa).

As well as the products listed here, we’ve also recently reviewed Alex Bellos’ new puzzle book and Vicky Neale’s book Why Study Mathematics?, and a specific gift guide for maths books for primary age children.

### Toys and Games

#### Genius Square (Maths Gear) – £16.97

One of the many excellent products from the Happy Puzzle Company (I’m particularly excited about their collection of Unusual Fidget Toys), Genius Square is an award-winning dice-rolling strategy game.

#### Raspberry Pi 400 (Pimoroni) – from £66.90

If you haven’t been keeping up with the latest developments in tiny computer technology, it’s now possible to buy a Raspberry Pi that comes inside its own keyboard, so you just need to plug it into a monitor or TV.

If you’ve been waiting for the amount of faffing about involved to drop dramatically before joining in with tiny ‘puter tinkering (or, you’ve already got one of every model but somehow still don’t have enough Pis), now’s your chance.

## Puzzles

#### Girih Puzzle – $20.00

These beautiful geometric puzzles are based on Islamic tilings and come in several varieties, for endless tiling fun.

(They appear to be currently out of stock, but here’s a blog post by Laura Taalman with ways to 3D print them instead!)

#### A Puzzle A Day Calendar (Dragon Fjord) – kr150.00 (about £19)

Deep in the category of ‘I can’t believe I didn’t think of that first’, this laser cut wooden calendar challenges you each day to fit in the pieces so that only that day’s date and month are visible. 365* puzzles in one!

#### Geometry Puzzles in Felt Tip, by Cat Shearer – £9.00

A favourite of maths teachers and MathsJam attendees alike, Cat Shearer has been sharing beautiful hand-drawn mini geometry puzzles on her Twitter feed for over a year now. The pick of the 2018 puzzles has been compiled into a nice, reasonably-priced book.

(If you’re in the market for fun geometry puzzle books generally, don’t forget Ed Southall and Vincent Pantaloni also have two books out: Geometry Snacks and More Geometry Snacks).

## Things to wear

#### Parametric Design t-shirts, by Sam Hartburn – £19.00

Semi-regular Aperiodical contributor Sam Hartburn has launched a range of t-shirts featuring pretty parametric equation designs. With or without the underlying equations, the designs include spirally flowers, funky rainbow harmonographs and hypnotic ‘sophisticated’ (according to Wikipedia, where I go for most of my fashion advice) waves.

#### Pythagorean Theorem earrings (Cofactor Designs) – from $15.00

For pierced ear owners, New York-based mathematical jewellery outfit Cofactor Designs offer these dangly proofs of Pythgoras in solid silver or 3D printed in a range of colours (the ‘Casual collection’).

#### Pi Cufflinks (Maths Gear) – £6.91

And for the classy shirt-wearer, don’t forget the correct way to hold your cuffs together is using 2π (and wearing two can help with any π vs τ arguments you might find yourself in).

## Nice Things to Have

#### Cheese Degrees – Precision Cheeseboard (Maths Gear) – £9.47

If, like me, you demand precision in your cheese-cutting, this provolone protractor will allow you to brie super-accurate about your cheese slicing, with angles around the top for wedges, and several standard cheese measurements laid out across the bottom. An essential for any parmesan pedant.

#### Marvin’s Magic Rubik’s Amazing Box of Magic Tricks (John Lewis) – £24.99

Containing over 40 different tricks, illusions and effects to celebrate the 40th anniversary of the invention of the Rubik’s cube, this is surely an excellent gift for the one person you know who’s really into Rubik’s cubes but would also love to put on a full magic show.

#### Ultimate Solids of Constant Width (Maths Gear) – from £76.99

Having previously sold yellow plastic Solids of Constant width (Peter and I talked about solids of constant width in a recent podcast), Maths Gear are now offering a classier option, if you’d like a thoughtful and meditative gift for someone who appreciates the innate beauty of mathematically interesting shapes. Intended as a desk toy, these shapes have the same diameter whichever direction you measure in, and come in shiny or brushed metal in three colours.

#### Actual Turing Machine (thaMthaM) – €299

If you’re willing to spend a chunk on a gift for someone truly special (or yourself, of course) the makers of the thaMographe have branched out from weird rulers, and created a digital tabletop gadget you can use to compute (theoretically) anything any other computer can. Perfect for that one person you never know what to buy for!

Great list. The Pi 400 is also a Universal Turing Machine of course.

A few other suggestions on my Christmas Wish list of Mathsy books would be :

A Computer Called LEO: Lyons Tea Shops and the World’s First Office Computer by Geogina Perry

A Mathematical History of the Golden Number by Roger Herz-Fischler

The Wonder Book of Geometry: A Mathematical Story

by David Acheson (Hardcover)