let curling() =
  let pi = acos(-1.) in
  let r =  91. /. (4. *. pi) in
  let s = pi *. r**2. in
  let cx = 826. in
  let m = 19.97 in
  let a = (cx*.s) /. (2. *.m) in
  let f u t = [|u.(1); ( -.a) *. (u.(1))**(1. /.3.)|] in
  let tabt, tabx = RK.rk f [|0.;2.|] 0. 1. 25 in
  let c = Array.make (Array.length tabx) 0. in
  for i = 0 to Array.length tabx - 1 do
    c.(i) <- tabx.(i).(0)
  done;
  Mat.afficher [| c |];
  let g = T.initialiser "Curling" in
  T.tracer_xy g tabt c "Distance(t)" ~couleur:C.rouge;
  T.fermer g;
;;