## geometry

The division of plant cells is governed by their shape – just one example of how maths may reveal the fundamental laws underlying biology.

How to derive the famous quadratic formula from pictures, just like the Babylonians did.

Euclid's fourth axiom says that all right angles are equal. But isn't that obvious?

This week would have been the 100th birthday of Martin Gardner, who is deservedly credited with turning on several generations of people worldwide to the pleasures of maths! To mark the occasion here are some favourite puzzles that, apart from being fun, also lead to some serious maths.

The Mayan civilisation brought forth many great things — including this clever way of making a right angle.

Maryam Mirzakhani is being honoured for her "rare combination of superb technical ability, bold ambition, far-reaching vision, and deep curiosity".