Katz reviews some work that seeks to “decorate” a Person class to include teacher traits. A factory that creates a Person proxy decorated with Teacher properties is considered as an approach. But it is criticized.
...this code, by tacking close to vocabulary created to describe Java patterns, rebuilds functionality that exists natively in Ruby. It would be equivalent to creating a Hash of Procs in Ruby when a Class would do.
Correct use of Ruby can provide built-in support for modular patterns, Katz writes, adding, "we don’t see enough usage of them," and provides some examples.