This coda is called Shadow Twin; the instructions are in the photograph. What does the image offer? What kind of twinship is it?
Although Shadow Twin is the coda in the process, its prompt is to follow this photograph toward an epigraph for your whale fall. It’s a finding exercise, a library assignment for tuning a triangulation: the space between this image, an epigraph you find in the writing of someone else, and the whale fall you wrote (or imagined writing).
To do the triangulation: distill, in your mind, the feeling of this photograph, of the twinship of the trees. Then distill, in your mind, the feeling of your whale fall story, tuning particularly into any polarities or complementarities that animate it. Then with those two feelings in mind, turn to a library and start scanning for a short passage that forms its own compelling relationship to both of those feelings.
It might help to give the two distilled feelings a symbol or other representation. Perhaps you feel them as color tones and you make a little watercolor card for each that can sit next to you as you scan the library. Perhaps you give each one a key word that can act as a metonym for the whole resonant mood.
The library might be your own bookshelves. It might be a library building. There will be something arbitrary about choosing a starting point, or perhaps some book or section has already surfaced in mind. Go find your epigraph.
Alternately, you can follow the example of the poet-scholar Joan Retallack, who occasionally provides the epigraph she needs under a winking fancy-dress pseudonym, Genre Tallique.
Alternately again, if you did not write a whale fall or if the epigraph game falls flat, write a microstory of no less than three sentences and no more than three pages that involves a shadow twinship of the kind the trees in this photograph possess. Set your story in a place that has something in common with a cemetery on a transitional day between winter and spring.