This is my entry for the Clockwork Prince ARC contest. I think some explanation might be helpful:
The angel in the center represents Tessa, and the rays of light that come out of her wings represent her attachment to both Jem and Will. The quote placed between the two of them was said by Jem, and it meant to convey Tessa's struggle: Who is the right man? The quote above Jem is told from his POV about Tessa. The quote above Will is told from his POV about Tessa.