class program {

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

define xor() {
    move();
    move();
    half-turn();
    if (nextToABeeper) {
        pickbeeper();
        move();
        if (nextToABeeper) {
            pickbeeper();
            move();
        } else {
            move();
            putbeeper();
        }
    } else {
        move();
        if (nextToABeeper) {
            pickbeeper();
            move();
            putbeeper();
        } else {
            move();
        }
    }
    turnleft();
    move();
    turnleft();
}

program() {
    iterate (8) {
        xor();
    }
    turnoff();
}

}