Swedish artist Oscar Reutersvard is the "father of impossible figures." He was the first to deliberately make impossible figures (previously they occurred in artwork unintentionally due to lack of perspective skill). In 1934 he created the first impossible triangle out of a series of cubes. This was honored in 1982 on a Swedish stamp (seen on the left). Roger Penrose would later independently re-create the impossible triangle in its most familiar form. A few years later he created the first impossible staircase.
Over the years, Reutersvard has created literally thousands of impossible figures. All of them in Japanese perspective.
There have been numerous books published on his works in Swedish, Polish, and Russian.