BTW, is there any member who has formally studied the "donut=coffee mug" subject here? Topology. I'd like a good book recommendation for it please. I am interested in studying it.
Can't believe that we have a thread on Maths yet noone has bothered posting these videos here:-
^This is what made me love Maths. Before I used to dislike it.
For anyone having problem with Ricci calculus:-