The previous post, if it was a difficult read, please imagine what an ordeal it must have been to write. Here is a much simpler rendition of the main points:
There are these two detectives, and they bring in this dim-witted suspect for a lie-detector test. They put a colander on his head and sit him next to a photocopy machine on which they have pre-placed a paper face-down on the glass. Each time he answers a question, one of them hits the "print" button and out comes this piece or paper: "He's Lying". Faced with this proof, the suspect confesses.I haven't heard how the story ends.