This is using the Gestalt principle where we are using positive and negative space. The negative space of the coffee cup is actually a person talking and the top of the coffee cup comes out to be a thought bubble.
Look at a tree, a flower, a plant. Let your awareness rest upon it. How still they are, how deeply rooted in just being. Allow nature to teach you stillness. When you look at a tree and perceive its stillness, you become still yourself.