Transposing dimensions to others is confusing in general as neither the B nor the 3 is in front or behind. One is to the left and one is to the right when talking about position. A clearer way could be to speak of the order of appearance. The B comes first and the 3 follows, which would be understood as we read from left to right.
Sometimes you want to talk about the coke that's in the bottle. Sometimes you want to talk about the bottle itself. That's what this distinction is about.
A bottle of coke is a reference to the coke in the bottle. The word bottle is a qualifier, that indicates how much coke, or which body of coke you are talking about.
A coke bottle is a bottle. The ...
Grammatically, is structure "not + preposition + but + preposition + object" possible?
Yes, it is.
For example, can I say 'someone is lying not on but off the couch'? I mean 'someone is lying not on the couch but off the couch on the floor.'
No, you can't, but this is mainly because "off" does not function in the way that would be ...
"To follow on from something" means to happen after something, and often as the next part or stage of it (Macmillan):
Following on from last year’s success, we’ll be offering other similar
What I’m going to say follows on from what Elizabeth was
"To follow up on something" means (Merriam Webster) to do something in ...