(func f(x) sqrt (1 - x ^ 2))
(/ (sum (f (rand.u 100)) ) 100)
(setq trials (calc (sum (f (rand.u 100))) / 100))
(dotimes (i 100)
         (setq trials (combine trials (/ (sum (f (rand.u 100)) ) 100)))
         )
(histogram trials)


;; 0.7917415072488666
(func f(x y ) exp (- (x ^ 2 + y ^ 2)))
(/ (sum (f (rand.u 100) (rand.u 100)) ) 100)
;; 0.5653445361809497