The meme originates from Xzibit's expression known from MTV series Pimp My Ride, who would usually go: Sup dawg, we heard you like X so we put a Y in your car so you can Z while you drive.
It has from there changed into: Yo dawg, I (or we) heard yo like X so we put a Y in yo Y so yo can X while yo X.
Yo dawg, I heard yo and yo dawg likes yo yos so we put yo dawg in yo yo yo so yo dawg can yo yo while yo yo yo.
Yo dawg, we heard you like functions so we put a function in yo function so yo can derive while you derive.
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