2007), the United States Court of Appeals for the Federal Circuit said: The Supreme Court has defined the term "machine" as "a concrete thing, consisting of parts, or of certain devices and combination of devices."
It has been considered grounds for rejecting or invalidating a machine claim as being directed to a "mere aggregation" if the parts were merely associated with one another without interacting functionally.
[3] An illustration of a mere aggregation would be the "combination" of a bathtub and a pencil sharpener.
More recently, the "mere aggregation" ground of invalidity for a machine claim has been subsumed under obviousness.
Electronic circuits have usually been considered machines, although they may lack moving parts.