•  An object occupies a region of some three-dimensional extent; it cannot be a one-dimensional 

curve or two-dimensional surface.  

•  A particular quantity of liquid can occupy any region of a specific volume. 

•  A closed container is an object or set of objects that completely envelopes an internal cavity. 

•  An upright open container is an open container with the opening on top. 

An exploratory robot armed with such knowledge (and other machinery for connecting 
that knowledge with perception and cognitive models) could perhaps then make 
inferences about the use and function of an unusually shaped kettle with a nearly-
hidden spout: 

Tea kettle believed to have been designed by Richard Williams Binns, (1837-1903) with concealed 
spout, underneath the hand on the right.
The Next Decade in AI-