The mathematician Clifford Pick over has depressing way of reminding himself how long he has to live. He calculated that he has 10,000 days left to live, based on his age and life expectancy; then he drew a square grid with 10,000 squares—100 squares on each side. The grid hangs over his desk. Every morning when he comes in to the office, he crosses out one square, and sees his life pass by.
From “How to Use Your Eyes” by James Elkins