geometry
We celebrate the most famous of mathematical constants with a circle puzzle. 
The impossible becomes possible when you move into the third dimension. 
How calculating the height of a frustum gave a glimpse of the mathematical frontier. 

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. 