“One night he left the light on and just stared into space silently. “Every couple hours I would wake up, and he was just still sitting there, in the thinking man statue pose, just completely silent on the edge of the bed,” Grimes says. When she woke up that morning, he said to her, “I solved it.”

“One night he left the light on and just stared into space silently. “Every couple hours I would wake up, and he was just still sitting there, in the thinking man statue pose, just completely silent on the edge of the bed,” Grimes says. When she woke up that morning, he said to her, “I solved it.”

— Walter Isaacson