player.onChat("19-3", function () {
    agent.move(FORWARD, 1);

    player.say("ジグザグに鉱石を置きます");
    const MOVE_COUNT: number = 13;
    for (let i: number = 0; i < MOVE_COUNT; i++) {
        placeOre();

        let mod_i = i % 2;
        if (mod_i == 0) {
            // i が偶数のとき (mod_i == 0)
            agent.turn(RIGHT);
        } else {
            // i が奇数のとき (mod_i == 1)
            agent.turn(LEFT);
        }
        agent.move(FORWARD, 1);
    }
    player.say("鉱石を置きました");
});