public boolean translate(Polyomino poly, int dx, int dy){
        for (Point loc:poly.getTranslateLocs(dx, dy)){
            if (loc.y<0 || loc.x<0 || loc.x>=fWidth ||
                    contents[loc.y][loc.x] != null) return false;
        }
        poly.translate(dx, dy);
        return true;
    }