sentences: if something is returned to a thing then that something is added to that thing
docs: backlit_thing is tangible_thing. thing is substance. recovered_thing is living_thing. returning is giving. sometimes_change is good_thing. change is when_one_thing_becomes_another_thing. burnt_thing is tangible_thing. removable_thing is device. rembass is tangible_thing. refried_bean is tangible_thing.