"I know; thirteen."
"Yes; and they must be red and white."
"That is correct," responded the Professor; "but do you remember how many of each?"
The boys were silent.
"The top and the bottom stripes are red, and the intervening ones white. What do these stripes represent?"
"The original States."
"I see you have a pretty good recollection. I remember a class of over forty boys, on one occasion, which had only three boys who recalled that. Then we must have a field of another color, up in the corner."
"That is the blue field, with stars on it."
"Yes; but how many stars?"
"A star for each State."