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“Transposition”, a sliding block puzzle by Jacob Siehler

Start and finished states of a Transposition puzzle

This is just a quick post to tell you about a nice puzzle game I spotted on Mathstodon.

It’s called Transposition, and it’s a sliding block puzzle in the vein of the popular game Rush Hour. You’re given a grid that’s almost full of rectangular blocks, and you have to slide them around each other until the two coloured blocks have swapped places.

The puzzle was invented by mathematician Jacob Siehler, who says he used a computer search to generate a pool of puzzles, given the rules of the game. I took quite a while to solve all 5 “easy” puzzles – as with any logic puzzle, you need to play about for a while to get a feel for the mechanics. I hadn’t appreciated at first that the grey blocks don’t need to be in their starting places when you solve the board – only the coloured blocks need to in the right positions.

There are 26 puzzles at the moment, ranging from “easy” to “very hard”. Have a crack at it! I really enjoyed it.

Play: Transposition, by Jacob Siehler

Here are the mathematicians you nominated to go on the new £50 note

The Bank of England has released a preliminary list of names nominated by the public to appear on the new £50 note. I’ve done a bit of analysis on the list, and present here my findings.

To recap: the Bank asked for nominations satisfying the following conditions:

  • have contributed to the field of science
  • be real – so no fictional characters please
  • not be alive – Her Majesty the Queen is the only exception
  • have shaped thought, innovation, leadership or values in the UK
  • inspire people, not divide them

The released list consists of the names that were nominated in the first week, and belong to people who are real, deceased, and contributed to science ‘in any way’. They haven’t divulged the number of times each name was nominated, or the ineligible names.

Zeckendorf cup arithmetic

My 5-minute talk at the big MathsJam conference this weekend was about some stacking cups that my daughter is too young to appreciate. Here’s the really quick version, in just over a minute:

I gave the answer at MathsJam, but the title of this post contains a big hint that should get you there with a bit of googling.

This matrix joke is only barely worth your time

If you see me doing a maths thing, I’m probably wearing one of my maths t-shirts. I’ve got quite a few, but the one that reliably produces the much-sought-after look of total indifference even once I’ve explained the joke is this one:

Photo of a t-shirt with a drawing: 4 by 4 matrix with N E R D along the diagonal

It’s a NERD identity matrix, get it?

That t-shirt was made by Festival of the Spoken Nerd, and by the way they’ve recently put together some new designs.

It’s long bothered me that the nerd identity matrix contains so many zeros. It’s also only an identity matrix if $N = E = R = D = 1$. Surely there’s a joke matrix somewhere with a bit more meat to it?

A puzzle for another day

A few months ago, my faculty’s PR person sent an email round asking if anyone would like to write a puzzle for the Today programme’s “Puzzle for Today” slot, to be broadcast during the programme’s trip to Newcastle in Freshers’ Week. A colleague said this might be the kind of thing I’d like to do, which it was, so I started thinking, and eventually came up with a brand new puzzle which I thought would work well.

If you listened to the Today programme this Thursday morning, you’ll have heard not my name, but that of Dr Steve Humble, who’s got a lot more experience doing this kind of thing. Turns out, they wanted something more ‘visual and interactive’, so asked him instead. I think that was a polite way of saying they just didn’t like my puzzle. Oh well!

Steve chose a classic puzzle that coincidentally appeared on Twitter about a month ago, prompting much discussion. It’s a good puzzle, much better than the one I came up with, but I don’t think Steve was completely right to say “It is possible that you can always create a winning game” – that’s only the case if there are an even number of coins, but his statement said “around ten coins”. I suppose he might’ve meant that, starting from having a handful of coins, you can decide to only use an even number of them.

The upside is that I can now talk about the puzzle here, where someone might actually enjoy it.

The incredible palindromic hat-trick

Would you like to see something AMAZING?

I’ve made another one of my interactive online maths doodads. You should have a go at it right now. It doesn’t require any effort on your part, other than coming up with a positive integer.

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