player.onChat("20-4", function () {
    player.say("柱を調べて、先頭を1つずつ取り除きながら柱を並べます");
    let tower: number[] = [0, 0, 0, 0, 0, 0];
    inspectPillar(tower);
    for (let i: number = 0; i < 4; i++) {
        tower.shift();
        agent.move(RIGHT, 1);
        buildPillar(tower);
    }
    player.say("柱を並べました");
});