class program {

define half-turn() {
    turnleft();
    turnleft();
}

define turnright() {
    iterate(3) {
        turnleft();
    }
}

define go-back() {
    half-turn();
    move();
}

define goto-start() {
    while (notFacingNorth) {
        turnleft();
    }
    while (frontIsClear) {
        move();
    }
    half-turn();
}

define leave-beepers() {
    turnright();
    move();
    while (anyBeepersInBeeperBag) {
        putbeeper();
    }
    go-back();
    turnright();
}

define put-in-position() {
    if (frontIsClear) {
        move();
        put-in-position();
        move();
    } else {
        half-turn();
        while (frontIsClear) {
            move();
        }
        turnleft();
        move();
        turnleft();
    }
}

define move-pile() {
    while (nextToABeeper) {
        pickbeeper();
    }
    half-turn();
    put-in-position();
    while (anyBeepersInBeeperBag) {
        putbeeper();
    }
    turnleft();
    move();
}

define invert() {
    goto-start();
    while (notNextToABeeper && frontIsClear) {
        move();
    }
    if (frontIsClear) {
        move-pile();
        invert();
    } else {
        move-pile();
    }
}

define shift-pile() {
    go-back();
    while (nextToABeeper) {
        pickbeeper();
    }
    go-back();
    while (anyBeepersInBeeperBag) {
        putbeeper();
    }
}

define shift-column() {
    if (leftIsClear) {
        shift-pile();
        turnleft();
        move();
        turnright();
        shift-column();
    } else {
        shift-pile();
    }
}

program() {
    goto-start();
    leave-beepers();
    invert();
    shift-column();
    turnoff();
}

}