Urban put dots on a sheet of paper, with each dot representing a certain period - say, years, months, weeks or days. Assume that you are a healthy, lucky person with a lifespan of 80 years. Even if each dot represents a day, it comfortably fits in an A4 sheet. And if each dot represents something less, say, a year or month or week, it too fits in three-fourth or half a sheet of a normal size paper.