Three sandwiches

From Abraham Pais's contribution to Paul Dirac: The Man and His Work:

Throughout his life, Dirac maintained a minimal, sparse (not terse), precise, and apoetically elegant style of speech and writing. Sample: his comment on the novel Crime and Punishment: 'It is nice, but in one of the chapters the author made a mistake. He describes the sun as rising twice on the same day.' Once when Oppenheimer offered Dirac some books to read, he politely refused, saying that reading books interfered with thought.
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... [At the Institute for Advanced Study in Princeton] we would often have lunch together. It was on one of those occasions that I had my first exposure to the Dirac style of exhaustive inquiry. Because of a large appetite and a Dutch background, I would regularly eat three sandwiches at that time. One day, Dirac queried me. (Between each answer and the next question there was a half minute's pause.) D. Do you always eat three sandwiches for lunch? P. Yes. D. Do you always eat the same three sandwiches for lunch? P. No, it depends on my taste of the day. D. Do you eat your sandwiches in some fixed order? P. No. Some months later, when a young man named Salam visited me at the Institute, he said: I have regards for you from Professor Dirac in Cambridge. He wants to know if you still eat three sandwiches for lunch. Dirac and I often lunched together when he came back to the Institute for the academic year 1947-8. On an early occasion, Dirac looked at my plate and noted, triumphantly: 'Now you only eat two sandwiches for lunch.'