As part of learning how to write, I have been reading Kate Wilhelm’s Storyteller, her reflections on 27 years of the Clarion Writers’ Workshops. One section talks about how she works “from images, to scenes, to incidents, then situations and finally plot” in contrast with either pantsing or the usual kind of plotting. The images often arose from her subconscious, her “Silent Partner;” plotting is essentially knitting together the scenes and incidents into a coherent order, adding new material to connect the old. Diana Gabaldon describes a somewhat similar process, and in a brief conversation with Nalo Hopkinson on the 2015 Writing Excuses Retreat cruise she told me she writes this way, too.
All of my NaNoWriMo novels started with images or very brief scenes. So after the riots on January 6, my reactions crystalized around a small number of images.