The document defines and provides key features of common 2D shapes including triangles, quadrilaterals, regular polygons, and circles. It describes properties such as lines of symmetry, rotational symmetry, and relationships between shapes. Special types of shapes are defined, such as equilateral triangles, isosceles triangles, right-angled triangles, rectangles, squares, parallelograms, trapezoids, rhombuses, kites, and regular polygons.