step - 15

Game.kt

return when (first to second) {
    // classic rules
    SCISSORS to PAPER,
    PAPER to ROCK,
    ROCK to SCISSORS -> FIRST_PLAYER

    // additional modern rules
    ROCK to LIZARD,
    LIZARD to SPOCK,
    SPOCK to SCISSORS,
    SCISSORS to LIZARD,
    LIZARD to PAPER,
    PAPER to SPOCK,
    SPOCK to ROCK -> FIRST_PLAYER

    else -> SECOND_PLAYER
}