player.onChat("20-1", function () {
    let height = 5
    let width = 5
    for (let i = 0; i < 3; i++) {
        for (let j = 0; j < width; j++) {
            for (let k = 0; k < height; k++) {
                agent.place(FORWARD)
                agent.move(UP, 1)
            }
            agent.move(DOWN, height)
            agent.move(RIGHT, 1)
        }
        agent.move(LEFT, width)
        agent.move(BACK, 1)
        height += -1
        width += -2
    }
})