class program {

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

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

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

define goto-corner() {
    while (notFacingSouth) {
        turnleft();
    }
    while (frontIsClear) {
        move();
    }
    turnright();
    while (frontIsClear) {
        move();
    }
}

define goto-start() {
    goto-corner();
    turnright();
    move();
    turnright();
    move();
}

define copy-pile(dist) {
    if (nextToABeeper) {
        pickbeeper();
        copy-pile(dist);
        putbeeper();
        go-back();
        iterate (pred(dist)) {
            move();
        }
        putbeeper();
        go-back();
        iterate (pred(dist)) {
            move();
        }
    } else {
        move();
        iterate (pred(dist)) {
            move();
        }
    }
}

define fibonacci() {
    while (frontIsClear) {
        copy-pile(1);
        go-back();
        move();
        half-turn();
        copy-pile(2);
    }
}

program() {
    goto-start();
    fibonacci();
    turnoff();
}

}