standing on the porch

A teenager wanting to earn some money, decided to hire himself out as a
handyman-type and started canvassing a wealthy neighborhood.
He went to the front door of the first house and asked the owner if
he had any jobs for him to do. "Well, you can paint my porch. How much
will you charge?"
The kid said "How about 50 dollars?" The man agreed and told him
that the paint and ladders he might need were in the garage.
The man's wife, inside the house, heard the conversation and said to
her husband, "Does that boy realize that the porch goes all the way around
the house?" The man replied, "He should. He was standing on the
porch."
A short time later, the teen came to the door to collect his money.
"You're finished already?" asked the man. "Yes," the teen answered, "and I
had paint left over, so I gave it two coats. "
Impressed, the man reached in his pocket for the $50. "And by the
way," the teen added, "that's not a Porch, it's a Ferrari."