Watch the video below from BBC Bitesize KS2 Maths which shows the lines of symmetry on a square, triangle, rectangle and circle.

That’s why a line of symmetry is sometimes called the mirror line. Sometimes you can fold a shape in half, and if it fits into itself perfectly with no overlaps you have found a line of symmetry.

What is particularly astonishing about the Red Square, the researchers say, is the degree of symmetry seen in lines, or "rungs," that bisect its surface. The rungs appear as shadows, and their ...