Design Principles of MC Escher
This first picture by MC Escher uses the gastalt principle of figure and ground. By drawing the goose in the way that choose and way they are positioned next to each other allows him to create the shape of a fish between each goose. The different colours used for each animal helps define their shape and details.
The second image uses the principle of similarity and continuation to repeat the image of the tree and birds over and over again without breaking up to give it a good flow and still be able to distinguish between each element