Piet Hein was a Danish polymath, often writing under the Old Norse pseudonym Kumbel, meaning "tombstone". His short poems, known as gruks or grooks, first started to appear in the daily newspaper Politiken shortly after the German occupation of Denmark in April 1940 under the pseudonym "Kumbel Kumbell". He also invented the Soma cube and the board game Hex.
Piet Hein (Kumbel) in front of the H.C. Andersen statue in Kongens Have, Copenhagen, 1983
Piet Hein's superegg in brass
The Soma cube is a solid dissection puzzle invented by Danish polymath Piet Hein in 1933 during a lecture on quantum mechanics conducted by Werner Heisenberg.
The pieces of a Soma cube
The same puzzle, assembled into a cube
An easier variant of the puzzle, where alternating cubes have different colors