(* To compile this example: ocamlc graphics.cma grtest2.ml -o grtest2 *)

Random.self_init ();;
Graphics.open_graph " 640x480";;

let rec iterate r x_init i =
  if i = 1 then x_init
  else
    let x = iterate r x_init (i-1) in
    r *. x *. (1.0 -. x);;

for x = 0 to 639 do
  let r = 4.0 *. (float_of_int x) /. 640.0 in
  for i = 0 to 39 do
    let x_init = Random.float 1.0 in
    let x_final = iterate r x_init 500 in
    let y = int_of_float (x_final *. 480.) in
    Graphics.plot x y
  done
done;;

read_line ();;