A way that Lily and Nina "complete" each other that NO ONE noticed.
I've searched around to see if anyone else ever noticed it... they didn't. So, allow me to just say... FIRST!
Anyway...
Lily and Nina are ALPHABETICAL opposites, or two halves of the same whole, depending on your interpretation. Allow me to 'splain.
Consider that each letter of the alphabet has a numeric counterpart: A=1, B=2, C=3, etc., up to and ENDING at Z=26. (See how I wrote that in all caps? That means it's important.)
L(12) + N(14) = Z(26)
I(9) - I(9) = 0 (cancel each other out)
L(12) + N(14) = Z(26)
Y(25) + A(1) = Z(26)
Nerdy? Absolutely. But when you consider the symbiotic relationship between the two characters, there's no way it was an accident.
(On a side note, I've posted this before and it was somehow deleted from IMDB. I find that interesting.)