Sky and Water 1

Came across this Escher print today while out on a visit, & decided I'd blip it!
This was a high quality numbered print! :-o

According to Escher: "In the horizontal center strip there are birds and fish equivalent to each other. We associate flying with sky, and so for each of the black birds the sky in which it is flying is formed by the four white fish which encircle it. Similarly swimming makes us think of water, and therefore the four black birds that surround a fish become the water in which it swims."