If you think of a hole as positive space instead of negative space, then you can think of digging a hole as something like sculpting. Pour metal into the hole and you’ll get a sculpture that corresponds to the empty space.
This is worth considering because there is a guy, an entomologist named Dr. Walter Tschinkel, who pours aluminum into ant hills and digs up the resulting forms. As it happens, these castings are beautiful sculptural things. How do those ants, one by one, silently, in the dark, work it all out?
Here is a CBS News story on the subject: The Secret World Of Ants.
(Seen on Ben Fry’s blog)