This "perfect #tea strength chart" pops up from time to time, and I struggle with the #maths of it.

At first glance it appears to show how tea strength changes in two variables. One variable is labelled 1-6, the other A-F, but (here's my first problem) it is not specified what is being varied along each axis. One *could* be brew time; the other *could* be milk quantity, but I don't know for sure, and even if I'm right there's no way to tell which is which.

Further, it appears to me that mugs along the same 45⁰ diagonal running from bottom left to top right have exactly the same colour. This may indicate that (if my guess at the variables is correct) any colour change introduced by altering brew time can be offset by changing milk quantity (and vice-versa), but this feels dubious.

I'm more inclined to believe that there is actually only one variable at work here (if pushed, I would guess that it's the amount of milk), and that instead of 36 different strengths of tea there are actually only 11.

I think this 2D chart should really be a 1D spectrum, and that the conductors of the study have chosen an unnecessarily complicated visualisation which implies things that aren't true. It's almost as if this isn't the result of dedicated and rigorous academic practice.

**What are the most important/influential #Maths #books of the 21st century?**

This is a very loose question, I know. That's intentional: I'd like to see how people interpret things like "important", "influential", and even "maths" and "book".

Given that, an explanation with your chosen book(s) would be most appreciated.

Also: I know that confining it to the last 24 years makes it more difficult as there hasn't been a lot of time for anything published in that period to have much influence at all. Humour me!

If you don't have an answer I'd appreciate a #boost all the same.

Thanks!

I don't do new year's resolutions, but all the same it's as good a time as any to change something, or start something, or renew something. I'd like to do more writing this year, but I want it to be useful for some subset of people rather than just an outlet for me.

So...

1. If you consider yourself to be a "not-maths" person in some way (or lack confidence, or struggle(d) with it), I'd like to answer any #maths-themed questions that you have. I'm not talking homework or exam questions. I'm thinking your personal queries _about_ maths more generally. Stuff like "what does nth mean?", or anything else that you may be wondering. I occasionally post maths stuff at tommaths.blogspot.com .

2. If you've got a burning question about #space, Blogstronomy still exists, though it's been very quiet for a while now. Maybe drop me a line and ask your question? (You can check I haven't already answered it here: blogstronomy.blogspot.com)

3. If you think I might be able to write about something mathsy for your blog, website, publication (or museum exhibition) I'm totally up for that even (especially?) if you think there's no way maths could fit with what you do. I tend to link to external work I've done here: tkbriggs.co.uk/topics/portfoli… (though it does need updating).

How Long Does it Take the Moon to Orbit the Earth?

Question posed by Elly. The Moon is a popular subject on Blogstronomy so I was surprised to find that this question hadn't been covered ...

^{TeaKayB (Blogger)}

Pythagorean Theorem Found On Clay Tablet 1,000 Years Older Than Pythagoras

"The conclusion is inescapable. The Babylonians knew the relation between the length of the diagonal of a square and its side: d=square root of 2," mathematician Bruce Ratner writes in a paper on the topic.

iflscience.com/pythagorean-the…

#math #maths

Pythagorean Theorem Found On Clay Tablet 1,000 Years Older Than Pythagoras

It predates Pythagoras by over 1,000 years.

^{James Felton (IFLScience)}