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Ohioans measure a really big π


Ohio State University mathematician Niles Johnson got in touch on Friday to tell us that our π Approximation Challenge last year had inspired him to hatch an audacious plan to measure a really big π.

The word ‘geometry’ is derived from the Greek for ‘measurement of land’, and Dr. Johnson took that quite literally: he wanted to measure the Great Circle Earthworks in Heath, Ohio; a part of the Newark Earthworks (not their original name) built over 2,000 years ago.

Rodents of Unusual Size? I don’t think they exist

A man in London claims to have found a rat ‘the size of a small child’, near a children’s play area in Hackney, London. Alongside a photograph of gas engineer Tony Smith proudly displaying the gigantic creature held in the jaws of a litter picking stick, some news outlets have reported the claim that the rat was “about four foot long”.

Photograph: Tony Smith/SWNS

Photograph: Tony Smith/SWNS

Luckily, mathematicians are here to save the day! Firstly, there’s no way it’s four feet long, as this rigorous analysis shows – estimating the height of the man as 180cm, and using the respective lengths of two of his visible fingers and the width of the litter picker at each end to estimate the effect of perspective:

Furthermore, several other people have successfully managed to recreate the effect of holding something relatively small up in a photo, putting it nearer the camera, and making it look much bigger, including The Guardian’s new formats editor Martin Belam, and in one brilliant case, an employee of Hackney council:

The message to the maths outreach community is that if we try really, really hard, we should eventually be able to get people to understand the thing where closer objects look bigger, although it may take more staring at model cows and pointing at cows out the window than was previously hoped.

More Information

Giant rat ‘the size of a small child’ found near Hackney playground, in the London Evening Standard

How to fake a giant rat (and why you shouldn’t trust pictures on the internet), on The Guardian

Hackney council made a wonderful response to that ‘rat as big as a 4-year-old’ story, at The Poke

Improbable John Conway/Pizza Hut collaboration for π day

John Conway, here pictured browsing the character table of $Fi_{23}$

Restaurant chain Pizza Hut in the US have announced a promotion for “Pi Day” on March 14, involving an unlikely partnership with renowned group-theorist, Life-wrangler and apparent pizza-lover John Conway. (Apparently, pizza and pie are somehow linked in America. It is probably best not to worry about this.)

Featuring on their blog as the inaugural post under the optimistic tags ‘math‘ and ‘John Conway‘, they explain that three maths puzzles set by Conway will be posted on Pi Day, “varying in level of difficulty from high school to Ph.D. level”. Residents of the 48 contiguous US states can leave their answers in the comments when the puzzles are posted, and the winners receive a 3.14-year supply of pizza (or, as the rules clarify, a somewhat more prosaic $1600 Pizza Hut gift card).

Obviously we will have to wait for the questions to be unveiled to be able to judge the appropriate level of excitement for this promotion, but with Conway involved, no maths-is-really-hard nonsense in the blog post, and not a formula for the perfect anything in sight, things are looking promising for a nice bit of harmless maths/poor childhood diet fun.

More information

Pizza Hut partners with mathematician John H. Conway for National Pi Day math contest – the blog post announcing the competition

John Conway on Wikipedia

Relatively Prime Season 3 Kickstarter

Relatively Prime - Kickstart Season 3

Samuel Hansen’s Relatively Prime has now published all episodes of the second season, available at, and the Kickstarter for Season 3 is now live. In fact, it’s so live it’s almost run its course: the third season will only be funded if at least $24,000 is pledged by Saturday 12th March 2016 at 4am GMT. At the time of writing, as I just pledged my support, the project is 30% backed.

Consider supporting this third season of stories from the mathematical domain! You can watch a video of animated Samuel telling you about the project, listen to Samuel speaking about why you should support this, or read an interview Samuel did about Relatively Prime with Shecky Riemann at Math-Frolic. To drum up your enthusiasm, you can listen to existing episodes or read our own Colin Beveridge’s recaps of season 2. Don’t delay too long, though – go to Kickstarter and pledge to support the project now!