Along the same vane from the math world is how natural numbers (which can then be used to build the reals, etc) are represented using only empty sets. Pretty a

Along the same vane from the math world is how natural numbers (which can then be used to build the reals, etc) are represented using only empty sets. Pretty awesome. See http://en.wikipedia.org/wiki/Set-theoretic_definition_of_natural_numbers http://en.wikipedia.org/wiki/Set-theoretic_definition_of_nat...