Sphere [circle]
This form has no edges or corners. It’s dynamic, meaning it in itself has a sense of motion.
Even so, a circle can be created by drawing a series of intersecting lines going different directions. And a sphere is defined by the intersections of countless conceptual planes.
Circles and spheres are considered complete and perfect.
While we can draw a cube and a pyramid as volumes using only lines, we need shading to show the volume of a sphere.
Cube [square]
A cube is made of 6 intersecting planes. This results in 8 corners and 12 edges. All the planes meet at right angles, making corresponding sides parallel. If all angles aren’t right (90˚) angles, the form is not a cube.
Unlike the sphere — and because of the edges and corners — we can draw a cube using lines alone, with no shading, and it is perceived as a volume.
When all 6 sides are equal in length and width, we have a square cube. If the cube is compressed, making some lengths shorter, it will appear rectangular.
The cube is also considered complete and perfect. But unlike the sphere, it is grounded and static.
Pyramid [triangle]
Pyramids have a base and non-parallel sides that converge to form a point.
The base of a pyramid is a square, and the form has four sides with triangular faces.
Pyramids are stable but also dynamic. The wide base and narrow apex create stability, but the diagonals create the perception of movement.
When inverted and placed on its apex, the form becomes physically unbalanced and unstable.