Whoever invented the knock-knock joke should get a no bell prize.
The longer you wait to reset the sign to zero, the higher your score. But don't wait too long, or someone else might reset it!
Whatever you do, you must not press the red button.
Just like word magnets you might find on a fridge, but online!
Press and hold the button for a long as you can endure. You might even get on the leaderboard!