This is a print image entitled Day and Night by the Dutch graphic artist, Maurits Cornelis Escher (1898 - 1972). His print style, using a mathematical mind and shapes to create visual optical illusions called tesselation. The flying bird shape was employed by Escher for he observed "that the silhouettes of birds and fish are the most gratifying shapes of all for use in the game of dividing the plane. The silhouette of a flying bird has just the necessary angularity, while the bulges and indentations in the outline are neither too pronounced nor too subtle. In addition, it has a characteristic shape, from above and below, from the front and the side .... " This image, created from two woodblocks, was originally produced by him in 1938. There is speculation and theory that the image is a statement on the worry of a potential World War II. Your print image of Day and Night is a reproduction of this 1938 image published in 1960 for Ballantine at Meredith Press. It is a later copy and unsigned. The estimate is based on actual recent past recorded auction sales of comparables. Retail 'asking prices' can be higher and vary.