what something is made of is a public of that something
man_made_pollution_source is tangible_thing. newspaper_office is tangible_thing. public_square is not tangible_thing. public_service_vehicle is not tangible_thing. newspaper_office is not tangible_thing. public_square is tangible_thing. public_high_school is tangible_thing. man_made_pollution_source is not tangible_thing.