Rhythm
Rhythm is a principle that represent a regular repetition of elements of art to produce the look and feel of movement in a work of art. Rhythm is found in music, dance, poetry, and theatre.
Visual Rhythm
Visual rhythm is rhythm that you can see with your eyes. Visual rhythm is created by repeating shapes in a certain pattern. Visual rhythm create a sense of movement in the work of art.
Contrast
Contrast refers to the arrangement of conflicting (opposite) elements in a work of art. Contrast would be light vs. dark colors, rough vs. smooth textures, large vs. small shapes, etc.