@jd Hope I didn't mess your post with my comment. There was a book or two published I've read about where different authors each wrote a segment.
In the Writers group I belonged, we did a short story the same way. I took it towards an outer space adventure, the next writer complained and the group helped her come up with Dallas's waking from a dream episode to bring it back to earth. I was suitably filled with faux indignancy, it was a lot of fun.
I was looking forward to writing a section and started writing. It was looking good too when I noticed the character count. 1024 characters isn't enough! For me anyway. I had to delete most of the descriptive text leaving what I felt like a shell of the original.
I tried to stick with the 'what' and leave it open for others to pick up. Choosing a subject was a process, it had to be important, immortality came to mind and it was perfect.
