What's the significance of the grandfather clock in Elfen Lied?

Question

In the anime Elfen Lied, Kouta and Yuuka own a grandfather clock that, if I recall correctly, has been broken for quite some time prior to the start of the series. At the very end of the final episode, Kouta and Yuuka sit down (with Nana and Mayu, I believe) to start their new life... only for the grandfather clock to mysteriously start chiming, apropos of nothing, just as

a figure implied to be Lucy approaches the front door.

I never understood what the deal was with the grandfather clock, and why it suddenly began working again at the end. I'm guessing that it must be symbolic of something, but I can't think what it might be symbolizing. If it's meant to symbolize Kouta moving on with his life, then

Lucy apparently showing up again rather ruins that.

What is the significance of the grandfather clock in Elfen Lied?

Answer 1

My personal interperation of the clock was always that it symbolizes the start of a normal live for Kouta and company. Which in place would fit really well with the ending of the rhyme elfenlied which insinuates the 'elf' observing, hitting it's head on a stone with Cuckoo sounds.

"What are those bright windows?
There must be a wedding inside;
The little people are sitting at the feast,
And make merry in the hall.
So I'll just take a peep inside!"
— Fie! he hits his head on hard stone!
Well, elf, had enough, have you?
Cuckoo! Cuckoo!

Some people however, also suggest that it might be Nyu, as opposed to Lucy. With the clock chiming in the start or maybe even birth of Nyu, into the world of normal humans.

Personally I think this was left open in a way it could be interpreted both in a positive and a negative ending. This both to drive people to read the manga which has a slightly different story and to stay in line with the rhyme, as this can be interpreted in both a negative and a positive tone.

Answer 2

In the final episode, after the clock scene, the dog starts making noise and then Kouta goes outside and sees a figure in the entrance of the house (that must be Lucy). So, it might be Lucy who used her invincible vectors to fix the clock from a distance and that shows us that her power somehow got enhanced (got longer vectors etc.).

Also, keep in mind that the only person who ever played with the clock in the anime was Nyu (the second personality of Lucy). So, the clock is related to Nyu.

And I conclude that by fixing the clock, it's the creator's way to make it clear to us that Lucy was alive and returned to the house of Kouta.