Final answer:
The design element that includes creating an effect by breaking the principle of unity is variety. It provides contrast to a composition and can create a focal point or emphasize certain elements.
Step-by-step explanation:
The design element that includes creating an effect by breaking the principle of unity is variety. Unity refers to the sense of completeness and cohesiveness in a work of art, while variety provokes changes and awareness. It provides contrast to a composition and can create a focal point or emphasize certain elements. For example, in a painting with a field of dark purple, placing a string of gold will create emphasis and make the gold lettering pop out.