Visual art can express an inherent energy that flows from a harmonious balance of contrasts. Opposites push and pull, and an artist must learn to direct that push and pull. This contrast can apply to every element of art, from value to color to line to form.
It can bridge the drawing to the painting; it can resolve the difference between the abstraction and representational.
What is it that makes this photo of clouds dynamic? Is it not the push and pull, the contrast of the deep shadows of the cloud mass to the bright airy sunlit edge of the cloud?
If you were to trace the dark outline of the cloud mass with your finger, and then do the same with the outline of the lighter cloud, the two lines would be very similar. Similar but different. Imagine if the two outlines were identical! Yuck! Our heavenly Father would never do something so monotonous in His visual artistry! Because the two lines are similar but different, they create a contrast, a visual push and pull that is pleasing and even dramatic to the senses.