My question about Neo stopping the Machine weapons got me to thinking, since both answers (so far) have brought up the point that "reality," in this case, is just another matrix.
I never really gave the sequels much thought, since they weren't as compelling to me as the first movie, but now this has me wondering.
Are there other clues or indications that the real world, the one with Zion, is another virtual reality? Is it possible that the whole concept of using humans as a power source is inefficient and won't work well a clue? (Or is it just an underthought justification for the machines keeping humans alive?)
(Note: I know this asks for something that may be a list of items, but this is a finite list. I've discussed that with moderators who feel there's a difference between an open ended list and one with a limited number of possible items. Please don't add "Me, too" answers with only one item.)