visualizingmath:

Impossible Figures - Art by Oscar Reutersvärd

Oscar Reutersvärd (1915–2002), widely acknowledged as “the father of the impossible figure”, was a Swedish graphic artist who in 1934 pioneered the art of 3D drawings which may initially appear feasible, yet cannot be physically constructed. Born on November 29, 1915 in Stockholm, Sweden, he reportedly suffered from dyslexia and had difficulty estimating the distance and size of objects. But his family was artistic, and encouraged his painting and sculpture efforts.

Do these look possible to you?