Recently Derin has made a new linguistic development.
A week ago Derin told me that the garage was a cave. Then 3-4 days ago he changed that. Now the garage is LIKE a cave.
A couple of days ago he also said that one of his toys was LIKE a tunnel (it was one of thoes spiral wire things to run beads along).
This seems to be an important linguistic/logical distinction that he is now making.