You're reading: Posts By Christian Lawson-Perfect

Some different ways of multiplying numbers, vectors and matrices

Here’s a quick video I recorded at the end of my work day, inspired by this tweet.

Aperiodical News Roundup – October 2020

Here’s a roundup of mathematical stories from the month that’s just been.

The enormous difficulty of telling the truth about escalators with statistics

Earlier this year, when getting the train to work was still a thing for me, I noticed this statistic:

Did you know? 95% of the time escalators were working in the last four weeks.

The permutation clock

52 playing cards arranged in a grid

I recently had an idea: map the Unix time (seconds since 1st January 1970) to shufflings of a deck of cards. Each second would correspond to a different ordering of the 52 cards.

I wanted to think about how mind-bogglingly huge $52!$ is: $52!$ seconds is more than $2 \times 10^{60}$ years. So even if you spent your entire life watching this thing, you’d leave this world having seen basically none of the possible permutations. Happily, Wikipedia reckons that the heat death of the universe will happen in about $10^{100}$ years, so there’s plenty of time for me to enact my plan.

Aperiodical Round Up 11: more than you could ever need, want or be able to know

Gnomon by Athanasius Kircher. Astrological symbols are arranged around an arch, with grid lines emerging from each. Some cherubs who look like they know what they're doing are in the middle with measuring sticks and a globe.

Hello, my name’s Christian Lawson-Perfect and my main mathematical interest is “everything”.

Before The Aperiodical existed as its own thing, the only outlet I had for my mathematical eclecticism was a series of posts on the Acme Science blog called Aperiodical Round-Up. Eventually I stopped writing them, as work and family took up more of my time. This post has been sitting in The Aperiodical’s drafts folder for six years. Time to finish it!

Let’s begin with the first 10,000 digits of π dialled on a rotary phone.

The Big Lock-Down Math-Off, Match 26

Welcome to the twenty-sixth and final match in this year’s Big Math-Off. Take a look at the two interesting bits of maths below, and vote for your favourite.

Here are today’s two pitches.