• 2D shapes are flat. Squares, rectangles, triangles and circles are 2D shapes.

• A regular 2D shape has all sides the same length and all angles the same size.

• A right angle is a 'square corner'. Four right angles fit together without leaving any gaps. 

• 3D shapes are solid like a brick, or hollow like a box. Cubes, cuboids, pyramids, cylinders, spheres and cones are 3D shapes.