*Plus* has teamed up with the Royal Society Summer Science
Exhibition 2011 to reveal the maths behind some of the science on show. The
*Maths Inside* project is run by the Mathematics Promotion
Unit (a collaboration between the London Mathematical Society and the Institute of Mathematics and its
Applications) in conjunction with *Plus* and the Royal Society.

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. You can read the articles by clicking on the links below and if you
can't make it to the exhibition yourself, you can also download pdfs
of the postcards.

*Image from postcard courtesy of http://www.beautycheck.de/*

Face to face — How can maths change your gender?

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? Peter McOwan and his colleagues from Queen Mary, University of London and University College London are using mathematical wizardry to produce gender reversed images of your very own face.

Can triangles help spot a bomb — How triangles help airport security staff

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.