German Conquest of Poland

Okay, listen up, you chucklehead. You're the kinda guy who probably thinks a history book is just a bunch of paper with old-timey scribbles on it, right? This joke is playing on the idea that the Germans, you know, from World War II, could trick the Polish by walking in reverse. Like, the Polish were too dumb to understand a basic military move. It's not real, it's a joke, get it?