
Impossible triangle was firstly painted in 1934 by swedish
painter Oscar Reutersvärd. He drew his version of traingle as a set
of cubes in parallel projection. Althow, many painters used impossible
triangle in their art, Oscar Reutersvärd did open the fantastic
world of impossible figures. He created thousands impossible figures
for his life and now he is known as "father" of impossible
figures. In 1980 Swedish goverment decided to place
impossible triangle and two other his figures at postage
stamps, which were printed about two years.. 

But the shape of impossible triangle is also well known as
Penrose tribar. In 1954 english mathematician Roger Penrose after the
lection of holland artist M.C. Escher drew impossible triangle in
it's common view. Unlike Reutersvärd's triangle, he painted triangle as three bars connected with right angles. He gave
perspective effect to it, which increased effect of impossibility. He
published his version of triangle in British Psychology Magazine in 1954 in
joined article of he and his father Lionel Penrose. In 1954 Escher had
not created his famous lithographs "Waterfall",
"Ascending and
Descending" and "Belvedere"
yet. Note, neither Penrose nor Escher had not knew about artworks
by Reutersvärd and Piranesi at that time. 