The Book of Kells features "zoomorphic" designs. Basically, animals that are twisted, stretched, and bent into 2-D designs. A bird might be chewing on his foot, his toes and beak woven like a piece of cloth. A dog's neck is stretched longer than a giraffe's and interlaces with those of four other dogs just like it to form a Celtic knot. "Zoo" for "animal." "Morphic" for "formed/morphed/changed."
And of course, intricate Celtic knots and swirling designs of many colors fill the pages.
The only real zoomorphic design in the film, (although certain creatures morph into other forms) appears when Crom Crúiagh is chasing Brendan.
The film has iconic images, like the book. Some people are lumps or rectangles with heads. Aiden has squared-off fingers. The edge of the forest is very organized: the tallest trees form arches for the ones beneath.
This images are also highly detailed and contain Celtic designs, like The Book of Kells.
The film also plays with perspective: A person in the distance will pass behind a tree and suddenly they are much, much closer. This depiction represents the actions going on. It's not meant to be taken literally, it's art. It's similar to changing angles on a film camera, except it all happens in the same frame.
In order to respect copyright laws, I have not put pictures in this post. However, here are some links so you can see the features I discussed:
The Chi Rho page, (mentioned in the film!): The Book of Kells
Besides Celtic designs, the page of the manuscript contains a zoomorph man, iconic figures, and animals.
See the gallery, it contains the images I was talking about: The Secret of Kells
This is an informative video on The Book of Kells: http://www.youtube.com/watch?v=HMvfMVBhUXI
On a side note:
Symbolism is found in the depiction of certain characters. The presence of monks from all over the world (Africa, Asia, Italy, and Ireland) at Kells symbolizes the fact that Ireland was an important center for Christianity during the period. It was a beacon of light in the Dark Ages. (See previous post for more on dark and light).