Joke from Thanksgiving

My dad and I were partners playing 8-ball against my grandfather and my uncle. Somehow, 4 of our balls had formed a perfect evenly spaced wall across the table, with all of our opponets balls behind it. I said, "we have an amazing defensive wall, we can't lose." My dad responded with, "Yeah that things like the Maginoe line... nobody could get through that, right?" At which point my uncle shot straight through the wall and made a shot. So I said, "I guess the gap between the 11 and the 13 must have been Belguim." My dad laughed a lot. I than observed that an amazingly low proportion of people would have found that funny, if you are not one of those people I appologize for wasting your time.