I don't know it for sure, but the number 7 and 16 seemed like a bible verse to me (since the movie contained many religious codes inside it, I just figured it could be some kind of a verse in bible) Since, the zion was in the new beginning, I just looked up at Genesis chapter 7, verse 16 (New international version) which read "The animals going in were male and female of every living thing, as God had commanded Noah. Then the Lord shut him in." hmm... and other versions had similar meaning such as "7:16 And they that came, came male and female of all flesh, as God had commanded him. And Jehovah shut him in." well, this is just my opinion and doesn't relate to anything concrete, but those numbers (7 and 16) might have meant those verse which might suggest that 1. Neo is Noah of mankind 2. All the living beings in flesh (not machines) are spared in with him 3. by obeying God (architect? system?) 4. thus they might be saved from the destruction inside the ark (new zion?) 5. only a small portion selected by Noah was saved in the great flood, and in matrix 2, neo has to select those few (7 males, 16 females?) kind of interesting :-)....