Explain a concept in two or three words, Communicate this idea through your materials, techniques, and design. The design you choose should support your basic concept. The elements of design are line, value, color, shape, size, pattern, and movement. The principles are harmony, contrast, rhythm, repetition; gradation, balance, and dominance. When elements and principles work together well, you achieve unity, the ultimate purpose of design. And this brings us to where you find your subject matter and source material.