I never got the idea with MSG, but then, I’ve never heard of Madison Square, and I’m the guy around here who has to be careful even in his all-college-educated family to not make people feel pop-culture ignorant.
The Disney “D”. Boy I felt like an idiot when I realized that it was not in fact an upside-down, mirror-image “e” with a line through it. I don’t even know how I ever got that it my head, other than that it must’ve happened when I was a child and somehow just stuck.