I was in the middle of a monologue when my lines disappeared, erased from my brain like a computer disc by a magnet. Time stretched and indecision congealed; in that moment I couldn’t have told you the name of the play, let alone what I was supposed to say next.

Mysteries are tricky – like farce, the mix of ingredients and the clockwork progression must be precise. Most elements aren’t as they seem at the beginning, and the pleasure for the audience lies in solving the puzzle as things unfold. While a novel has the comparative luxury of making sure every piece is just right, a live production is complicated by technical limitations (lighting, sound and set), and especially by the actors: flubbed lines and inconsistent accents can irretrievably alter the recipe.