What's this??? A spin off?

Seperate story, same universe. Wouldn't call it a spin off

Oooo oookokoo I seee

It's actually the first series made by the author. Strange Picture is the first book and Strange House is the 2nd one followed by Strange Buildings (this is a sequel to strange house and is included as vol 2 in hen no ie). As you can see the contractor, kurihara from hen no ie was there in the first part of this story