Grook

A grook ("gruk" in Danish) is a form of short aphoristic poem. It was invented by the Danish poet and scientist Piet Hein. He wrote over 7,000 of them, most in Danish or English, published in 20 volumes. Some say that the name is short for "GRin & sUK" ("laugh & sigh" in Danish), but Piet Hein said he felt that the word had come out of thin air.