"A man and a woman making love in a park," the man replies.
The psychiatrist holds up the second picture and asks the man what he sees.
"A man and a woman making love in a boat."
He holds up the third picture.
"A man and a woman making love at the beach."
This goes on for the rest of the set of pictures; the man says he sees a man and a woman making love in every one of the pictures. At the end of the test, the psychiatrist looks over his notes and says, "It looks like you have a preoccupation with sex."
And the man replies, "Well, you're the one with the dirty pictures."