Years ago when I worked as a paramedic, we who worked for the fire department all knew a stoner cop who was going through the testing process, including the polygraph, to be promoted within the police department. He would have had a very hard time passing the polygraph with his ongoing history of weed use. So when it came time for his polygraph, he put a thumbtack in the toe of his shoe and practiced answering questions he knew would be on the exam, pressing his big toe down on the thumbtack so his body would reflect a similar stress response on every question. He used the thumbtack trick during the official polygraph. And he passed.

Which was sad, really, because in addition to being a stoner, he was a lying, cheating, married-but-womanizing snake of a guy who probably made the most crooked cop there ever was.