A 2D shape is symmetrical if you can draw a line through it and it looks exactly the same either side. This line is called a line of symmetry. Oh that rather smug expression tells me that square ...

This course explores some visual aspects of mathematics. Topics are chosen from areas such as geometric constructions, tessellations of the plane, symmetry groups, Platonic and Archimedean solids, ...

A 2D shape is symmetrical if a line can be drawn through it so that either side of the line looks exactly the same. The line is called a line of symmetry. This is sometimes called a 'mirror line ...