Self reference puzzle

A self-reference puzzle is a type of logical puzzle where the question in the puzzle refers to the attributes of the puzzle itself. A common example is that a "fill in the blanks" style sentence is given, but what is filled in the blanks can contribute to the sentence itself. An example is "There are _____ e's in this sentence.", for which a solution is "eight" (since including the "eight", there are 8 e's in the sentence).