matter with variable volume and shape takes the shape and size of its entire container
fluids has shape_of_containers solids has not definite_shape_and_volume container is container_shaped_object. objects has volume solids has definite_shape_and_volume container_shaped_object is cavity_or_container. container_independent_shape is finite_spatial_thing. fluids has not shape_of_containers container is not container_shaped_object. container_independent_shape is not finite_spatial_thing.