Thinking very hard about the same problem for several hours can produce a severe fatigue, close to a breakdown. I never really experienced a breakdown, but have felt "strange inside" two or three times during my life.

— Stanislaw Ulam Adventures of a Mathematician - Third Edition (1991)

More quotes by Stanislaw Ulam

Adventures of a Mathematician - Third Edition (1991)

Adventures of a Mathematician - Third Edition (1991)

Adventures of a Mathematician - Third Edition (1991)

Adventures of a Mathematician - Third Edition (1991)

Quote text and notes from Wikiquote: Stanislaw Ulam (page history), available under CC BY-SA 4.0. Source quality and labels are our own summary of what Wikiquote records.