Literally thousands of people have signed a petition to tell Libra that that’s not OK.

An advert for something which both men and women buy, like car sponges, with the tagline “absorbs way more than you ever did in maths class” would be disappointing, but not so bad. It’s not uncommon for people to dislike maths class, so alluding to it is an easy way to gain the consumer’s sympathy.

An advert for a maxi pad is different to an advert for a car sponge because of the long history of the rest of our culture telling women they’re not as good at maths as men. This advert reinforces that stereotype because there’s a conspicuous lack of adverts for products targetted at men that make reference to *their* poor maths skills.

University of Sydney professor Nalini Joshi, who has to spend a depressing amount of time talking about things like this, said in *The Australian* newspaper,

This is the way bullies work at school, by trying to separate you from the group and barraging you with messages that you don’t belong.

Twitter user @EatShootBlog has put it even more succinctly:

NOT BUYING LIBRA ANYMORE! My two teenage girls love maths. This is fucking ordinary. Lift your game! @LoveLibraX pic.twitter.com/PCgd5x1KO6”

— Trish (@EatShootBlog) August 11, 2014

Petition: Libra’s absorption problem

Women in science and maths denounce stereotyping in Libra tampon ad in *The Australian* (might ask you for a subscription if you don’t arrive via a Google search)

Shelley Bridgeman: The problem with this Libra pad ad in *The New Zealand Herald*

To celebrate the release of the upcoming Alan Turing biopic *The Imitation Game* (see our incisive analysis of the film’s trailer by James Grime) the guys at the University of Manchester – who have previously run the hugely successful Alan Turing Cryptography competition – have been asked to run a one-off Imitation Game Cryptography Competition. And they have.

The competition is themed around the (possibly true? Who knows. It’s not like it’s my job to research these things) idea that Alan Turing’s fortune in silver is buried in a secret location somewhere near Bletchley Park, and it’s your job to crack the three coded clues and find out where. Prizes will be in the form of exclusive *Imitation Game* merchandise donated by the makers of the film, and the competition runs until the 28^{th} of November.

The Carnival rounds up maths blog posts from all over the internet, including some from our own Aperiodical. See our Carnival of Mathematics page for more information.

]]>*For a lark, David and I have decided to review some of the Encyclopedia’s sequences. We’re rating sequences on four axes: Novelty, Aesthetics, Explicability and Completeness.*

**CP: **It’s Neil Sloane’s 75th birthday today! As a special birthday gift to him, we’re going to review some integer sequences.

**DC: **His birthday is 10/10, that’s pretty cool.

**CP: ***<some quick oeis> *there’s a sequence with his birthdate in it! A214742 contains 10,10,39.

**DC: **We can’t review that. It’s terrible.

**CP:** I put it to you that you have just reviewed it.

**DC: **Shut up.

**CP:** Anyway, I’ve got some birthday sequences to look at.

**DC: **About cake?

**CP: **No.

A050255

Diaconis-Mosteller approximation to the Birthday problem function.1, 23, 88, 187, 313, 459, 622, 797, 983, 1179, 1382, 1592, 1809, 2031, 2257, 2489, 2724, 2963, 3205, 3450, 3698, 3949, 4203, 4459, 4717, 4977, 5239, 5503, 5768, 6036, 6305, 6575, 6847, 7121, 7395, 7671, 7948, 8227, 8506, 8787, 9068, 9351

**DC: **I like Diaconis. That’s my first though. Don’t know who Mosteller is though. 3/5.

**CP: **Mosteller is/was a dude and/or ladydude.

**DC: **Will you explain the sequence please?

**CP: **I’ll try, but the OEIS entry doesn’t give us much to go on. It refers to a paper called “Methods of studying coincidences“. Which is a coincidence, because I’ve got that very paper right here. As far as I can tell, the approximation producing this sequence is their equation 7.5, i.e.

\[ Ne^{-N/ck}/(1 – N/c(k+1))^{1/k} = \left[ c^{k-1}k! \log_e \left( \frac{1}{1-p} \right) \right]^{1/k} \]

**CP: **Whew. Feel like checking that’s right?

**DC: ***<firm nods of the head>*

**The real DC: **SHAKES! SHAKES OF THE HEAD!

**CP: **OK, let’s get on with reviewing this in our four categories, which are well-defined and we understand completely.

**DC: **Zero. I still don’t know what they’re on about.

**CP: **It’s an approximation to the number of people you need to have in the same room to have a 50% chance that $N$ of them will share a birthday. *Some* would say it’s more hassle to work out this approximation than the real value.

**DC: **Can I look at this in graph form? I’m getting bored.

**CP: **OK…

**CP: **Well, it’s exponential.

**DC: **It’s linear!

**CP: **Do I need to draw a tangent on the bottom bit? Or maybe *point you to the equation of the function, which contains an exponential.*

**DC: **It’s a log to an exponential. It’s linear.

**CP: **Yeah, but you solve that for $N$.

**DC: **I think it’s linear. I say we get the random number generator out and move on.

**CP: **OK..

\[ \frac{6}{5} \text{ (generated by fair dice roll)} \]

**CP: **Jeez I am so sick of the birthday problem! Zero. Minus zero!

**DC: **Agreed.

\[ - \frac{0}{5} \]

**DC: **No, minus one. You said minus zero factorial.

\[ - \frac{1}{5} \]

**CP: **The graph is pretty but the equation is yuckly. I’m not sure.

**DC: **$\frac{1}{5}.$

**CP: **Won’t argue with that.

\[ \frac{1}{5} \]

**DC:** It’s an approximation. It can’t be complete.

**CP: **And apart from that, the OEIS entry is woefully lacking in detail. Not even a PARI formula, which is like the minimal possible usefulness because nobody uses PARI.

**DC: **Sloane should be ashamed of himself. I’ll let him off this once since it’s his birthday.

**CP: **Actually, it’s Eric Weisstein who’s to blame. Him with his own world of physics.

**DC: **When’s his birthday? I say we *don’t* review a sequence on his birthday, just to teach him.

**CP: **I can almost guarantee that’ll happen. Anyway, we need a score. There are a good number of elements in the OEIS entry.

**DC: **One of them’s palindromic as well. Did you see it?

**CP: **Four of them! In the first eight terms! This is a palindrome goldmine!

**DC: **But it’s got hardly any of the possible palindromes. $\frac{1}{5}$.

**CP: **This isn’t the “how many palindromes has it got” category. Because you’re not taking this seriously, I’m going to remove your voting rights for this category. So I say the score is:

\[ \frac{212}{515} \]

**CP: **Four. We just said so.

**DC: **Which isn’t many.

\[ \frac{1}{5} \]

**DC: **Let’s add up the scores!

**DC: **I say we get Wolfram Alpha to do it. It’s very complicated today.

\[ \frac{6}{5} + - \frac{1}{5} + \frac{1}{5} + \frac{212}{515} + \frac{1}{5} = \frac{933}{515} \]

**DC: **We need to divide by five.

**CP: **Yeah, we normally miss that part out in our calculations.

\[ \frac{933}{2575} \approx 0.36 \]

**CP: **Not a great score. In fact, that’s around about what I would’ve given it if we hadn’t been stupid in all five (out of four) categories. The system works!

**DC: **Woohoo! Now let’s bake Sloane a cake that he can’t eat.

**CP: **He actually nominated me as his cake-eating proxy in case of such circumstances as these.

**DC: **Are you sure, because *I’m* going to bake it.

**CP: **I was lying.

Puzzlebomb is a monthly puzzle compendium. Issue 34 of Puzzlebomb, for October 2014, can be found here:

Puzzlebomb – Issue 34 – October 2014

The solutions to Issue 34 will be posted at the same time as Issue 35.

Previous issues of Puzzlebomb, and their solutions, can be found here.

]]>While the festival brochure isn’t too specific about who’s speaking, this event is part of their ‘Conversations’ strand of researcher-led events, and promises to explain chaos, uncertainty, randomness and predictions.

Chaotic science cabaret – an open mic night for science, featuring speakers from a range of disciplines – including our own mathematician Katie Steckles (that’s me).

What Manchester-based mathematical walking tour programme would be complete without a random walk around ‘Turing’s Manchester’. Go to the places! In real life!

Following on from the success of Matt Parker’s Domino Computer in 2012, the MSF have invited him back to do something even more stupid and ambitious. Using over a million business cards in 20 locations around the world, Matt and a team of enthusiastic mathematicians will be building a giant fractal Menger Sponge, spanning the whole globe. Join in with the fun by turning up on the day, or visit MegaMenger.com to find out how to get involved.

This musical performance piece by theatre company Geddes Loom is about humans, maths and meaning with live-looped music, spoken word and storytelling. It’s been developed in collaboration with mathematicians including our own Katie Steckles (again me, sorry).

Alex Bellos, bestselling author of Alex Through the Looking-Glass and Alex’s Adventures in Numberland, dives into fractals, cones and curves to navigate a sea of numbers. Learn about the people he’s met on his mathematical book-writing journey, and find out the results of his Favourite Number survey.

The classic pub/maths combo strikes again, with this special Manchester Science Festival edition promising more pub, more maths and more celebrity guests (last year Marcus Du Sautoy popped in for a visit, as did Matt Parker and Colin Wright). Who knows who’ll turn up this time?!

John Edmark has 3d-printed a series of sculptures which do something rather remarkable when you rotate them. In the stop-motion animation above, the sculpture rotates by the golden angle in each frame.

**See more:** Blooming Zoetrope Sculptures by John Edmark at Instructables.

*via Henry Segerman on Google+*

Cory Doctorow described himself on boingboing as “a great fan of Relatively Prime” and the Chinook episode as “one of the best technical documentaries I’ve heard“. Tim Harford described it on Twitter as “a great podcast of storytelling about mathematics“.

This series was funded via a successful Kickstarter in 2011. This is where people pledge to support the project, but only have to pay if the project reaches its target, and get funder rewards in return. Maybe you supported it. I certainly did.

You probably also know Samuel is trying to raise funds via Kickstarter for a second series of episodes. Funder rewards include video updates from Samuel, stickers, a ‘zine, your adverts on episodes, the opportunity for Samuel to do voice work for you, right through to the chance to get involved with production of an episode. The deadline for funding is Tuesday October 21st, and Samuel has over 100 backers and is more than one third of the way to his goal. Maybe you’ve already pledged to support it. I certainly have.

Samuel is tweeting about the Kickstarter, and I am occasionally retweeting him. Katie wrote a blog post here at The Aperiodical about the project. However, it gets to the point where we are just telling the same people over and over, many of whom will have already pledged. What the project really needs is for you to help by telling other people about the Kickstarter. Can you tweet about it? Or post it somewhere other than Twitter? Can you write your own blog post about the project and/or why you chose to support it?

You can watch an entertaining animated video giving the pitch and embed the video in your own website or blog at the Kickstarter page.

Note: I have nothing to do with this project, have no inside information and do not benefit as a result. If you want to ask questions about the series or the Kickstarter, contact Samuel Hansen. Samuel has appeared on a couple of podcasts talking about the Kickstarter, and I know he is keen to do interviews to promote the idea.

I’ve used the Kickstarter page to embed the current total below, so people of the future can see whether my words offer a heart-warming story of success, or a tragically unheard cry for help. People of the present: you have the power to influence this outcome.

]]>*Android, iOS, £1.76/$2.99*

A really goofy game that fully owns its geek appeal: you play the last Star Nerd who battles to save the galaxy by doing sums. What’s not to love?

The gameplay is a mix of lane strategy and a deck-building card game, crossed with the Countdown numbers round; you play cards by combining the numbers you’re given using addition, subtraction or multiplication to reach the target score on a particular card. You get a bonus if you use up all your numbers, then you’re given another set of numbas and you get another bonus if you play all your cards.

The card-game mechanics and spacey setting give you more motivation to continue than the totally abstract *Quento*, covered last time, but eventually I got fed up with it – I played *Magic: The Gathering* once and found it completely unappealing – but I’m sure there are plenty of people whose brains will be expertly tickled by *Calculords*.

*Android, iOS, 60p/99¢.*

I didn’t really get on with *The Rectangles*, but Ed Pegg, Jr. of mathpuzzle.com loves it, so maybe I’m not clever enough to appreciate it.

*The Rectangles* is very simple: you drag rectangles in the direction of their long sides to push other shapes around. Grey shapes don’t move, and the aim is to push all the green squares off the board. It gets hard quite quickly.

*Android (but iOS imminent, I think), free or £1.79 to remove ads.*

It’s quite bold of *Sumico* to claim to be “**the** numbers game”, but I won’t hold that against it. Maybe it’s to distinguish from SUMICO Lubricant Co., Ltd.

This is another join-up-the-numbers-to-make-a-target game, but the second parent this time is Spelltower. When you combine two or more number tiles using the mathematical operation tiles, they’re replaced with a single tile containing the result of the calculation. The tiles accumulate score modifiers as you perform calculations with them, so there’s a lot to think about when deciding how to reach a target. I like how you have to really think about the laws of associativity – you get more points for splitting a calculation into a few steps, but sometimes that puts the other tile you need just out of reach.

Later levels add in multiplication, division, and “$x^2$”. In addition to the campaign, which introduces game mechanics gradually, there’s an endless mode that… doesn’t end.

I think I’m going to be playing *Sumico* for quite a long time.

*Android (72p), iTunes (69p)*

A new game from the people who made *Quento*! Happy hooray! In *Numolition*, you’re presented with a tower of numbered blocks, which you have to blow up. You can blow up sets of two or more adjacent blocks with the same number. Where it gets clever is that you can slide blocks horizontally, or add blocks by sliding them into each other (but you can’t go over 9). Solving levels usually involves doing a bit of adding-up to work out what groups of numbers you can make.

In a final twist, levels sometimes ask you to leave one block with a particular number at the end. Tricky!

** Previously: **Games to entertain a commutative mathematician, along with more recommendations in the comments.

Have you got a favourite mathsy game that I don’t know about? Please share it!

]]>For the second series, we’re promised between eight and sixteen further episodes (depending on how much money is raised) if the Kickstarter raises at least $15,000 by October 21.

Sam has made this rather impressive video to set out his pitch:

You can listen to the first series at relprime.com or using your favoured podcasting technology. And if you want to help make more happen you can contribute to the Kickstarter.

Relatively Prime, all in a name – guest blog post written here by Sam about the podcast.

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