a gruk

"A little beyond perception's reach, I sometimes believe that life is two locked boxes, each containing the others key"..a Gruk or more commonly known as Grook by Piet Hein.

Piet Hein was a Danish Polymath.

As per wiki :

A grook (Danish: gruk) is a form of short aphoristic poem or rhyming aphorism created by the Danish poet, designer, inventor, and scientist Piet Hein. He wrote over 7,000 of them from 1939 until his death in 1996, mostly in Danish^[2]. The grooks are multi-faceted and characterized by irony, paradox, brevity, precise use of language, rhythm and rhyme, and an often satiric nature. Many of the grooks have an accompanying line drawing, which provides additional meaning.