4 ms·This took me 15 s: 9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9by flemhans 5y agoThis took me 15 s: 9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9^9tihsllub 5y agoYou wincarl_dr 5y agoRead the article and take another 15s. That was one of the naive examples he gives near the start.