Ok. Just realized:
I’ve been trying to work with individual words but words are too small unless they are perfect which is rare. A sentence would be the atomic form I’m looking for. An incomplete sentence which affords slot-filling, whether in the form of a Fill In the ____ or in the form of a question, is the electron hole to be filled. A kind of theoretical word chemistry, complete with valance and bonds.
So, I could put an incomplete sentence, then branch off with various answers to complete the sentence, which could lead to further sentences until I reach an incomplete sentence again, which would require slot-filling exercise that can further branch.