In a dark room in central London two men sit down to play a board game. 19 days later, they are still there. Nobody has won a match. Something like the clinical definition of insanity springs to mind. And then the levee breaks.
Magnus Carlsen is thinking. He has been thinking for a while.
Since he was two years old, putting together 50 piece jigsaw puzzles. Since he was four, assembling LEGO sets for children three times his age. Since he was five, when he was taught the game that would become his life and since he was six and seven, when he would sit alone and play both sides of the board. Since he was eight, his first tournament, and since he was 13, the age he became a grandmaster; the same year that he drew with Garry Kasparov, the man many consider to be the greatest chess player of all time.
That is, if they don't now consider it to be Carlsen. On that day and at that age, he could - and should - have won.
He's been thinking since he was 14, when he was first nicknamed the "Mozart of chess". Since 15, when he became national champion. At 18 he did something that only four chess players had ever done before him: reach an Elo rating of 2800. He was thinking then, too.
Since 20, when he became the number one ranked player. Since 22, world champion. Since 24, when he defended the title and recorded the highest Elo rating ever recorded, a staggering 2882.
He is 27 now, and he is defending both the world title he has held since 2013 and his number one world ranking he has had since 2010. He is still thinking. He turns in his chair, away from the chessboard for the first time, and stares out into the audience behind the glass wall.
Magnus Carlsen, it seems, is stuck. Someone on the front row scratches down the list of moves with a pencil. 14. bxa5 Rxa5 15. Bd2 Raa8 16. Qb1 Nd7 17. Qb4 Rfe8
Someone else, sat on the floor in the corner of the room closest to the glass, appeared to do the same.