One-liner to compute if a chess game is a draw by repetition. I love this language.

    /// This function will return true if the same
    /// position occurs 3 times, at any point in the game.
    pub fn is_draw_by_repetition(&self) -> bool {
        self.history
            .iter()
            .rev()
            .step_by(2)
            .skip(1)
            .filter(|pos| pos.masks() == self.last.position().masks())
            .count()
            > 1
    }