(defn r-squared [x y]
 (+ (* (- 0.5 x) (- 0.5 x))
    (* (- 0.5 y) (- 0.5 y))))

(loop [hits 0]
  (let [x (rand)
        y (rand)
    something-goes-here)
    ;end-of-let
;nothing goes here. everything interesting must happen within the let, since if we put something here,
;then the loop would return the result of that, and not what happens inside the let.
)
;end-of-loop