if something comes from something else then that something else is a source of that something
else is river. change is when_one_thing_becomes_another_thing. source_materials is source. space is not what_between_else. directions_to_get_somewhere is not how_to_thing. source_materials is not source. change is not when_one_thing_becomes_another_thing. thing is substance. fault is not tangible_thing. directions_to_get_somewhere is how_to_thing.