That's Maths
thatsmaths.com · Personal blog · on HN since 2013
That's Maths is a blog on mathematics in everyday life and history, covering Fibonacci patterns, number puzzles and math in music.
What HN saysHN links it for accessible math history and nature posts; one commenter faults its rollercoaster piece for omitting Euler spirals and clothoids.
17HN people shared it
8linked it in comments
12stories submitted
46story points
6 months agolast shared
2013people per year2026
Most-shared posts
- 1Sunflowers and Fibonacci: Models of Efficiency (2014)2 people · 23 points · first shared 2023 · discussion on HN
- 2What did the romans ever do for maths2 people · first shared 2021
- 3Ramanujan’s Astonishing Knowledge of 17291 people · 4 points · first shared 2016 · discussion on HN
- 4Mowing the Lawn in Spirals1 people · 4 points · first shared 2020 · discussion on HN
- 5Which is larger, e^pi or pi^e?1 people · 3 points · first shared 2016 · discussion on HN
- 6Marvellous Merchiston’s Logarithms1 people · 2 points · first shared 2016 · discussion on HN
- 7Doughnuts and Tonnetze1 people · 2 points · first shared 2018 · discussion on HN
- 8The Power Tower1 people · 2 points · first shared 2013 · discussion on HN
- 9Hanoi Graphs and Sierpinski’s Triangle1 people · 2 points · first shared 2021 · discussion on HN
- 10Kepler's Magnificent Mysterium Cosmographicum (2016)1 people · 1 points · first shared 2020 · discussion on HN
- 11Modelling a Balanced Pencil(2014)1 people · 1 points · first shared 2026 · discussion on HN
- 12The Shaky Foundations of Mathematics1 people · 1 points · first shared 2016 · discussion on HN
- 13Torricelli’s Trumpet and the Painter’s Paradox (2017)1 people · 1 points · first shared 2023 · discussion on HN
- 14The power tower fractal1 people · first shared 2020
- 15Music and maths are inextricably intertwined1 people · first shared 2025
What HN people wrote when they linked it
chaoticmass · 2023-09-26
Plants may not have a concept of numbers or math, but they seem to follow mathematical patterns regardless.
https://thatsmaths.com/2014/06/05/sunflowers-and-fibonacci-models-of-e…
thaumasiotes · 2021-03-21
Wikipedia has plenty of citations to classical Rome.
Colosseum gate 44: XLIIII (not, for whatever reason, XLIV, or XXXXIIII)
18th legion: XIIX
22nd legion: IIXX
There was evidently not a strict standard.
(Note also that the symbols we use for high values, D and M, weren't really what the Romans used. You can see Roman abaci with columns labeled with place values: https://en.wikipedia.org/wiki/File:RomanAbacusRecon.jpg https://thatsmaths.com/2019/07/04/what-did-the-romans-ever-do-for-math…
Those look the same; I don't know whether the one is a replica of the other or whether the form was just that standardized. But the columns are plainly labeled as, in ascending order, ϴ, I, X, C, ∞, ((|)), (((|))), and |X|.
I speculate that ∞ is a fancy way of writing (|); I believe our M descends from Roman (|) and our D from Roman |). )
throwaway2562 · 2024-09-03
Guy writes 10 bazillion sub-lit-crit words on rollercoasters, fails to mention Euler spirals and clothoids, where the beauty is, where maths guides and protects meat. A depressing lack of curiosity by the author.
https://thatsmaths.com/2014/04/10/rollercoaster-loops/
fao_ · 2021-03-20
It's why arithmetical calculation was a role one had. They used an abacus for the calculation of complex sums.
https://thatsmaths.com/2019/07/04/what-did-the-romans-ever-do-for-math…
CogitoCogito · 2020-04-28
It's smart of you to bring up the surreal numbers: https://thatsmaths.com/2019/01/10/really-0-999999-is-equal-to-1-surrea…
godelzilla · 2020-01-22
This analysis can also be expanded to the complex numbers yielding "power tower fractals" aka "tetration fractals".
http://paulbourke.net/fractals/tetration/
https://thatsmaths.com/2016/04/14/the-power-tower-fractal/
bdcs · 2017-06-04
Wikipedia says the Trinity test was 20 kilotons. With Fermi estimating 10 kt, he was off by a factor of only two.
Of course Taylor got an estimate within 2 as well, using photographs published in Life magazine.
https://thatsmaths.com/2014/09/18/how-big-was-the-bomb/