[vhwltxbp] Written collaboration

A team collaborates on a project under the artificial constraint that their entire collaborative communication must be textual.

Perhaps a written work as the project, naturally.  Artistic written work suggests a novel.

At the end is not just the finished work, but also a textual record of the entire process by which it came to be, which is interesting in its own right.

What kind of platform best facilitates this kind of collaboration?  Humans are not really that great at textual communication for complex, subtle things: they would rather talk in person.