After a day of baseball and bicycling with the Digit aliens (see "The Alien Baseball Field"), you are growing hungry.
"Join us for a pie feast!" says Digit Three, leading you to a very long picnic table. Standing at one end of the table, you can't even see all the way to the other end; the table seems to go on forever.
The nine Digits scramble off into the woods. Moments later, Digit Three reappears with a humongous pizza and sits down in a special chair at the end of the table. Then Digit One appears with a meat pie and sits on the long bench to the left of Three. Four comes along with a spinach pie and sits beside One.
More Digits emerge from the woods, each carrying a different kind of pie. Another One sits beside Four with a cherry pie. Then comes Five with a blueberry pie, Nine with a peach pie, and Two with an apple pie.
As Six arrives to take a seat beside Two, the Digits invite you, Anita, and Bill to sit across the table. More digits keep coming, and they start passing around slices of pie to share.
"How many of you are coming?" you ask.
"Everyone is invited, and our current population is about 50 trillion," says Three, who is still sitting at the head of the table. "Our population keeps growing because we never die, and we keep on adding Digits."
As you contemplate the idea of eating pie with more than 50 trillion Digits, Bill looks up and down the row of Digits on the bench. He gets a befuddled look on his face. Anita studies the row of Digits and breaks out laughing.
What is so funny about the seating order?