Trivia: The Sator Square dates back to Pompeii and is a square of 5 Latin words making a palindrome: Sator, Arepo, Tenet, Opera, and Rotas. Whichever orientation the square is in the words line up in both directions. Each word features in the film - Kenneth Branagh's character is named Sator, the forger mentioned near the start is Arepo, the title is of course Tenet, the opening sequence takes place in an Opera, and the Ukranian special forces who arrive in that sequence have badges on their arms with "Rotas" on them.