Zevkten dört köse olmak (Lit. To have enjoyment from four corners) -- Idiomatic Meaning: To jump for joy, be very happy, be overjoyed….

The story... In Bursa during the 1930's, there was an authoritarian mathematics teacher named Kel Osman ('Bald' Osman) -- who terrified the distressed students of the leading High School there.

One day, when one of his students flubbed an exercise on the blackboard, Bald Osman raged at the poor unfortunate:

"Get out of my class! You're worse than an idiot. You're a donkey squared."

The teacher had meant, 'You are a donkey multiplied by a donkey' -- the height of stupidity, as far as he was concerned. But his students understood him to mean a 'square-shaped donkey'. And, confidentially, the phrase delighted them. So much so that they adopted it into their own 'private' vocabulary -- and they'd use it to tease a fellow-student whose math skills were weak, calling him (or her) a 'donkey-square'.

In time, the idiom migrated out of the math classrooms into the vocabulary of the entire student body, and in the process its original meaning metamorphosed. It started to mean a 'donkey with four corners' -- an image that the greater student body found irresistibly entertaining. So instead of being used for ridicule, it began to indicate joy and merriment to the highest degree. Students began to say things like, "I made four-corner fun", and, "I had fun from four corners."

The idiom 'left school' and took the whole city by storm. And when the traveling theatrical community got hold of it -- it wasn't long before you could hear it from Istanbul to Van.

One of the favorite 'vaudeville' acts of the time used to include this bit of 'comedic' silliness in its repertoire: