# Articles

Through the looking-glassSome molecules - thalidomide, for example - come in both left and right handed versions, while others are indistinguishable from their reflections.

*Plus*finds out about the role of mathematical**symmetry in chemistry**.
Getting into the pictureImagine stepping inside your favourite painting, walking around the light-filled music room of Vermeer's "The Music Lesson" or exploring the chapel in the "Trinity" painted by Masaccio in the 15th century. Using the

**mathematics of perspective**, researchers are now able to produce three-dimensional reconstructions of the scenes depicted in these works.
Dashing alongCurrently, disabled computer users have a hard time inputting text, using laborious word-completion.

*Plus*find out how this is changing, thanks to**Dasher**, a new open-source text-entry system based on**arithmetic coding**.
Text, Bytes and VideotapeHow can a 3 hour long film like the Lord of the Rings fit on a single DVD? Hw cn U rd txt msgs? How do MP3s make music files smaller, so they can be downloaded faster off the Internet? All these things rely on the mathematics of

**data compression**.
Newton and the kissing problemIn 1694, a famous discussion between two of the leading scientists of the day -

**Isaac Newton**and David Gregory - took place on the campus of Cambridge University. The discussion concerned the**kissing problem**, but it was to be another 260 years before the problem was finally solved.Editorial

- Information overload - how mathematicians are helping us all to make sense of the vast amount of information now available to us
- Sum problems - can you be good at mathematics without being good at arithmetic?
- Readers' corner - Meet Mandy, the cuddly Mandelbrot set!

The best medicine?To make hard decisions, you need hard facts.

**Medical statistics**can help us to decide what treatment to look for when we are ill, and to estimate our chances of recovery.
In a spinWhen it comes to the science of the very small, strange things start happening, and our intuition ceases to be a useful guide.

*Plus*finds out about the crazy**quantum world**, and spin that a politician would die for.
Mathematical mysteries: The gentlemen from Basle and the Petersburg Paradox

Just over 220 years have passed since the death of one of the most distinguished mathematicians in history: Daniel Bernoulli, who died on March 17th, 1782. The name of Bernoulli asks for precision since the family from Basle produced no fewer than eight outstanding mathematicians within three generations.

More or LessA new series of

*More or Less*, BBC Radio 4's series devoted to all things numerical, starts on November 12th. Presenter**Andrew Dilnot**tells*Plus*about the motivation behind the programme.