A human can comprehend approximately two numbers.
That’s it.
Don’t ever offer a bunch of numbers to a human at the same time. Try to offer only two numbers at any one time. Feel like a wild, risk-taking kind of guy? OK, offer three numbers at a time. Beyond that? A waste of time.
Knowing this important secret of the universe, go forth and prosper.


St. Louis, Winter 1967: I was 
San Francisco, 1976: You have dialed (415) 751-4022. A click, and one of those new answering machines begins speaking. It says …