Counting In The Courtyard

A group of people were touring a university campus and they noticed
several students on their hands and knees assessing the courtyard with
pencils and clipboards in hand.

"What are they doing?" a woman asked the tour guide.

"Each year," he replied with a grin, "The upperclassmen ask the freshmen
how many bricks it took to finish paving this courtyard."

When we were out of earshot of the freshmen, the woman asked the guide:
"So what's the answer?"

The guide replied: "One."