module creating_marks
  depends on embodying
  sort declarations
    mark :: embody, produce
    print :: mark

    physical_object :: tangible_entity
    inanimate_object :: physical_object
    piece_of_substance :: inanimate_object
    physical_mark :: piece_of_substance

    artifact :: inanimate_object
    physical_document :: artifact

    document :: message

  axioms
    false if instance(X, mark),
             result(X, R),
             -instance(X, physical_mark).


    false if instance(X, print),
             object(X, O),
             -instance(X, document).

    false if instance(X, print),
             result(X, R),
             -instance(X, physical_document).