> Toulouse noted that Poincaré kept very regular hours. He did his hardest thinking between 10 a.m. and noon, and again between 5 and 7 in the afternoon. The 19

> Toulouse noted that Poincaré kept very regular hours. He did his hardest thinking between 10 a.m. and noon, and again between 5 and 7 in the afternoon. The 19th century’s most towering mathematical genius worked just enough to get his mind around a problem—about four hours a day. The two 2-hour hard thinking hours chart was the most useful takeaway for me.