A man was on a cross-country flight with his young son. The man had work on which he was trying to concentrate. But the son, with little to engage his attention, frequently distracted the man. In one of the airline magazines, the man found a map of the world. Knowing his son loved puzzles, he tore out the map and ripped it into small pieces, which he put on the boy's tray table.
"There," said the man. "We made a puzzle. Now you can put the pieces together."
Seeing his son's eyes light up, the man assumed he'd bought himsef an hour or so of concentration. But five minutes later, the boy tapped his father's arm.
"All set, Dad."
"How did you put the world back together so quickly?" the man asked in disbelief.