Rock, Paper, Scissors game in OCaml

RockPaperScissorsGame.ml

type gesture =
  | Paper
  | Rock
  | Scissors

type result = 
  | Win of gesture * gesture
  | Lose of gesture * gesture
  | Tie of gesture

let hand g1 g2 =
  match g1 with
  | Paper ->
    (match g2 with 
    | Rock -> Win(g1, g2)
    | Paper -> Tie g1
    | Scissors -> Lose(g1, g2))
  | Rock ->
    (match g2 with
    | Rock -> Tie g1
    | Paper -> Lose(g1, g2)
    | Scissors -> Win(g1, g2))
  | Scissors -> 
    (match g2 with
    | Rock -> Lose(g1, g2)
    | Paper -> Win(g1, g2)
    | Scissors -> Tie g1)

let gesture_to_string g = 
  match g with
  | Paper -> "Paper"
  | Rock -> "Rock"
  | Scissors -> "Scissors"

let result_to_string res = 
  match res with 
  | Win (g1, g2) -> ("First player's " ^ gesture_to_string g1 ^ " beats second player's " ^ gesture_to_string g2)
  | Lose (g1, g2) -> ("Second player's " ^ gesture_to_string g2 ^ " beats first player's " ^ gesture_to_string g1)
  | Tie g -> ("Two " ^ gesture_to_string g ^ "s, the game is tied")