## News from the world of Maths

What's a particular piece of mathematics good for? It can take decades, or even centuries for an answer to this question to materialise. In today's climate, in which scientific research is increasingly judged according to its impact, this can pose a problem for pure mathematics. Now a collection of examples of mathematical ideas that have found applications long after their discovery has been published in the journal Nature.

Sometimes people are nasty when it would have been better to be nice.

Professor John Barrow, director of the Millennium Mathematics Project (the home of Plus), wins the IMA-LMS Christopher Zeeman Medal for his work promoting mathematics to the public.

How would it feel to look in a mirror and see not your own reflection but instead how you would look as the opposite sex? You can explore this strange alternate reality at this year's Royal Society Summer Exhibition where scientists from Queen Mary, University of London and University College London will use mathematical wizardry to produce gender reversed images of faces.

*Plus* has teamed up with the Royal Society Summer Science
Exhibition 2011 to reveal the maths behind some of the science on show. We have chosen two exhibits from this year's participants and produced
postcards for people to pick up at the stand, accopmanied by *Plus* articles to reveal some of the the maths behind
them. Read the articles and if you
can't make it to the exhibition yourself, you can also download pdfs
of the postcards.

Airport security staff have a daunting task. With impatient queues looming over them they need to search x-ray scans of cluttered suitcases for several items at once: knives, guns and bombs. How can we ease their task and make sure they don't miss a crucial item? To find out, scientists are trying to understand how we humans take in visual information. The humble triangle plays a crucial role in the experiments they perform.

A Rubik's cube, you'll be pleased to hear, can always be solved in at most 20 moves, no matter how badly it was scrambled up to start with. Mathematicians have proved that that's true. But what if you're wrestling with a larger cube that has more than three little cubes in a row?

*Plus*!