Piet Hein (December 16, 1905 – April 17, 1996) was a Danish scientist, mathematician, inventor, author, and poet, often writing under the Old Norse pseudonym "Kumbel" meaning "tombstone". His short poems, gruks (or grooks), first started to appear in the daily newspaper "Politiken" shortly after the Nazi Occupation in April 1940 under the pseudonym "Kumbel Kumbell."
He was born in Copenhagen, Denmark. He studied at the Institute for Theoretical Physics of the University of Copenhagen (later to become the Niels Bohr Institute), and Technical University of Denmark. Yale awarded him an honorary doctorate in 1972. He died in his home on Funen, Denmark in 1996.
He was a direct descendant of Piet Pieterszoon Hein, the Dutch naval hero of the 17th century.
He is known to a wider public for his thousands of short, aphoristic poems called Grooks (Gruk in Danish) and creations like the games of Hex, Tangloids, Morra, Tower, Polytaire, TacTix, Nimbi, Qrazy Qube, Pyramystery, and the Soma cube. He advocated the use of the super ellipse curve in city planning, furniture making and other realms. He also invented a perpetual calendar called the Astro Calendar and marketed housewares based on the Superellipse and Super-egg.