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 knows ...

Three lines of symmetry on an equilateral triangle. Right-angled triangles follow the same rules as other triangles. It's not the right angle that matters but whether the triangle is scalene or ...

There's something inherently pleasing about things that match – from matching pillows on a couch to matching paintings on either side of a room. These elements create a sense of cohesion, balance, and ...