The Impossible Triangle is an optical illusion
, first attributed to Swedish artist, Oscar Reutersvärd
, in 1934. Originally, he drew the shape with strings of cubes, rather than solid bars.
The more familiar version (shown below) was created independently by Roger Penrose after attending a lecture by Dutch artist, M. C. Escher in 1954.
/ / \
/ / /\ \
/ / /\ \ \
/ / / \ \ \
/ /_/____\ \ \
/__________\ \ \
Escher, in turn, was inspired to create images, including his famous "Waterfalls"
image, by the work of the Penroses.
In 1980, the Swedish government honoured Reutersvärd by using his original image on a stamp between 1982 and 1984.