"In the midst of discussing Aristotle's Poetics I suddenly asked, 'Exactly what is the principle of that walk of yours! Are you trying to avoid the flowers on the rug, or are you trying to keep to the squares?' My own compulsion neuroses made it easy for me to notice them in others.
"He wheeled around sharply: 'You're the first person who has caught me out,' he said. 'No, it's not the flowers or the squares; it's a habit that I have got into of doing things in sevens. I take seven steps, you see, then I change direction and go another seven steps, then I turn around. I consulted Browne, the Professor of Psychology, about it the other day, but he assured me it isn't a dangerous habit. He said, "When you find yourself getting into multiples of seven, come to me again."'"