I don't think a concrete submarine would work very well. :)

More seriously, I have no idea. Submarines normally involve an advertisement for the advertising company somewhere in the latter part of the article; no company = no giveaway ad. But knowing Trump and his way with memes, I wouldn't be surprised if the author just had walls on the brain, without having to be paid for it...

Why? Is building the wall going to mess up the "it's not possible" and "it won't work" narratives you've been been trained with?

I seriously hope no one thinks we're going to go to war against Mexico...