Wikipedia:POTD column/May 14, 2006

Uncle Sam is a national personification of the United States dating from the War of 1812. During World War I and World War II, Uncle Sam's image was used for military recruitment in this poster. The poster uses an artistic trick: if the pupils are drawn exactly centered in the eyes of a portrait, this gives an impression that the portrait "looks back" at the viewer wherever the viewer stands.

Image credit: James Montgomery Flagg
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