What the fuck is this??

(defun tak (x y z)
  (if (>= y x)
      z
      (tak (tak (- x 1) y z)
           (tak (- y 1) z x)
           (tak (- z 1) x y))))

>>1
Hmm, it seems like it's a clever way to return the median of three integers. That's pretty cool, I might have to make a note of this.