How do you write a computer program that creates the illusion of stretching elastic bands between pegs of a Geoboard? The answer contains some surprising mathematics.

The triangle ABC is equilateral. The arc AB has centre C, the arc BC has centre A and the arc CA has centre B. Explain how and why this shape can roll along between two parallel tracks.

A triangle ABC resting on a horizontal line is "rolled" along the line. Describe the paths of each of the vertices and the relationships between them and the original triangle.

Can you explain what is happening and account for the values being displayed?

Use the animation to help you work out how many lines are needed to draw mystic roses of different sizes.

Choose a couple of the sequences. Try to picture how to make the next, and the next, and the next... Can you describe your reasoning?