Humpty Dumpty

Why do we assume Humpty Dumpty was a gigantic anthropomorphic egg? Apparently the poem was originally a riddle, but there are lots of things besides eggs that can’t be reassembled after falling from a height and breaking. Not even by a bunch of horses.

Maybe Humpty Dumpty was a massive defense robot. Maybe he was sabotaged. Maybe the reason no one could put him together again was because he was a remnant of a bygone era, left behind by a world that moved on, and all knowledge of the ancient technology that created him was lost generations ago.