Johnny baked a single \'pī\ for his friends, and when his friends asked for more \'pī\ so that each friend could have one \'pī\ , he responded with
"I gave you two \'pīs\ already!"
His friends were confused, since Johnny had obviously only given them one \'pī\ ...
How do you get two \'pīs\ out of one \'pī\?
(If you are wondering what the slashes are and symbols are, they indicate pronunciation, probably a part of the puzzle...)