RPS: Linear, Non-Linear, or Sandbox?

I believe Rock, Paper, Scissors, is a non-linear game. The reason being is that there are different ways to play the game, and different outcomes during gameplay. Its not linear in that the outcomes are random, and the game is flexible. Its not sandbox because its not an open customizable game with almost unlimited options. Its non linear because it has defined rules but there are those options in gameplay and the randomness to it.