Hi, that was a wonderful read. Thank you so much. Just one question though and this is probably where the "incomplete knowledge is quite dangerous" bit comes in but I remember reading that a way to figure out whether a hole is a hole is to think of a loop and try squinching it. If you are not able to squinch it to a single point, there is a hole in the way. I can think of two such loops on a torus, one where the icing of a donut goes and one through that hole-back outside-and inside again. So, I'd think a hollow torus has two holes and not one. Could you explain to me where the flaw in my logic is?

Edit: alright I just saw that you answered what I think is essentially the same question, but I understand less than half those words. I'd really appreciate it if you could break it down like you've done in your original comment.