let rec escapesRec cr ci it zr zi =
    if it == 0 then false
    else if (zr*.zr +. zi*.zi) > 4.0 then true
    else escapesRec cr ci (it-1) (zr*.zr -. zi*.zi +. cr) (2.0*.zr*.zi +. ci)

let escapes cr ci it = escapesRec cr ci it 0.0 0.0

let toChar b = if b then ' ' else 'X'

let main () = 
    let xmin = -2.0 in
    let xmax = 1.0 in
    let ymin = -1.0 in
    let ymax = 1.0 in
    let xstep = int_of_string Sys.argv.(1) in
    let ystep = int_of_string Sys.argv.(2) in
    let iterations = int_of_string Sys.argv.(3) in
    for yc = 0 to ystep-1 do
        let y = (float_of_int yc) *. (ymax -. ymin) /. (float_of_int ystep) +. ymin in
        for xc = 0 to xstep-1 do
            let x = (float_of_int xc) *. (xmax -. xmin) /. (float_of_int xstep) +. xmin in
            print_char (toChar (escapes x y iterations))
        done;
        print_char '\n'
    done
    ;;

main ()