o.println(right(t.id, 3));
o.print(right(t.id, 3)); if (t.interleaved) o.print('x'); o.println();
    void print_order_rec(PrintStream o, BddTree t, int level) {        if (t == null)            return;        if (t.nextlevel != null) {            for (int i = 0; i < level; ++i)                o.print("   ");            // todo: better reorder id printout            o.print(right(t.id, 3));            o.println("{\n");            print_order_rec(o, t.nextlevel, level + 1);            for (int i = 0; i < level; ++i)                o.print("   ");            // todo: better reorder id printout            o.print(right(t.id, 3));            o.println("}\n");            print_order_rec(o, t.next, level);        } else {            for (int i = 0; i < level; ++i)                o.print("   ");            // todo: better reorder id printout            o.println(right(t.id, 3));            print_order_rec(o, t.next, level);        }    }