You'd get a score at the end based on how many times the frustrated poster was fooled by the player pretending to not get the idea.
Example:
Poster: "Custard Filled Speed Bumps."
"Speed bumps that are hard if you drive into them quickly, but soft if you are at the required safe speed."
Player:
"But won't they taste bad after cars drive over them?"
Mark: "You don't eat them, the custard analogy is just to illustrate the firmness of the speed bump."
Player: "So it can be a speed bump that you also eat?"
Mark: "No, again, for the second time you don't eat it!”
Player: "Then why use custard at all? Why not some substance more appropriate for putting inside a speed bump that does the same thing?"
Mark: "Jesus, IT'S NOT CUSTARD! THAT'S JUST AN EXAMPLE OF THE FIRMNESS OF THE GOD DAMN SPEEDBUMP!"
Player: "So why NOT use custard?"
Mark: "BECAUSE THAT WOULD BE FUCKING STUPID!"
Player: "Didn't mean to upset you, just think you could have picked something a little less distracting than custard, because custard is delicious."
Mark: "Oh... wait... you got me. What's the score?"
Player: "LOL! Four, but I get bonus points for the all caps sentences and swear words, so 4/2/1.
Mark: "Well played."