From my father-in-law:
A Jewish man took his Passover lunch to eat outside in the park. He sat down on a bench and began eating. Since Jews do not eat leavened bread during the eight day holiday, he was eating matzoh, a flat crunchy unleavened bread that has dozens of perforations.
A little while later a blind man came by and sat down next to him. Feeling neighborly, the Jewish man passed a sheet of matzoh to the blind man.
The blind man handled the matzoh for a few minutes, looked puzzled, and finally exclaimed, “Who wrote this garbage?”