WHEN WE ADD DIFFERENT SHAPES TOGETHER WE CREATE A DIFFERENT FEELING.
A handle on a cup adds a new dimension to the cylinder.
An annex to a room, or an ornament added to the outside of a building will create a different feel.
Often basic shapes are added together to create the main form of a building. A pyramid can top a cube.
BELOW ARE IMAGES SHOWING 2 SHAPES ADDED TOGETHER