public void findNextPositions() {
	Position next = currentPosition.top();
	while(next.valid()) {
	    addNextPosition(next);
	    next = next.top();
	}
	next = currentPosition.right();
	while(next.valid()) {
	    addNextPosition(next);
	    next = next.right();
	}
	next = currentPosition.bottom();
	while(next.valid()) {
	    addNextPosition(next);
	    next = next.bottom();
	}	
	next = currentPosition.left();
	while(next.valid()) {
	    addNextPosition(next);
	    next = next.left();
	}
    }