How did I not know this? The decimal expansion of 2017 repeats every 2016 digits!

Saw this lovely, if slightly knacked, adding machine in the Sun Inn, in Morpeth. You stick a stylus (or a finger) in one of the holes and drag it down to add to a column. It was a bit rusty and skipped digits more often than not.

I'm on holiday in the Hague. Here are some of the things I've seen

Spotted this nifty Cairo tiling on my hotel room wall in Den Haag

never mind , I'm concentrating my efforts on the real future of mathematics:

Mrs L-P had a very happy accident at the photo printers

You know how something can be 'over-engineered'? Well, I think some things are over-mathematicianed.
This bouncy ball, on sale for a couple of quid next to the tills at Mothercare, is a fine example. It's made of six rubber threads, woven together to make a shape with dodecahedral symmetry, such that each face has five different colours. Why six threads? So it can embody the outer automorphism group of \(S_6\)!
It was invented by Dick Esterle. This is my daughter's one; my dog has a bigger one.

Recently I discovered a surprising fact about numbers, so I made an online web thing to give it the recognition it deserves. Give it a go:
A little write-up on @aperiodical at

I really love capturing the state of a highly viscous fluid at a snapshot in time, AKA baking a marble cake 🎂 😛

I've been enjoying playing Rikudo Puzzles on android -
It's like Simon Tatham's Signpost game, but on a hexagonal grid. You have to place numbers in the cells to form a contiguous path which fills the entire board. I don't get much out of the timer and stars for finishing quickly - I just like solving the puzzle. Placing numbers can be a bit fiddly - it's very easy to accidentally switch to counting backwards, or miss out a number.

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A Mastodon instance for maths people. The kind of people who make \(\pi z^2 \times a\) jokes.

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