WGR 3.4.1 Automating the Creation of Attributes
Attribute assignment with symbols is way shorter.
attr_writer and attr_reader don't require their own 'end's apparently?
attr_accessor & attr
WGR 3.5 Inheritance and the Ruby class hierarchy
3.5.1 Single Inheritance: one to a customer
WGR 3.5.2 Object ancestry and the not-so-missing link: the Object class