See this example:

``` ruby
module ExampleModule
  def example_method1
    "This is example method one"
  end
  alias :example_method2 :example_method1
end

class ExampleClass1
  include ExampleModule
end

example1 = ExampleClass1.new
example1.example_method1 #=> "This is example method one"

class ExampleClass2
  include ExampleModule

  def example_method1
    "This is alternate universe example method one"
  end
end

example2 = ExampleClass2.new
example2.example_method1 #=> "This is alternate universe example method one"
example2.example_method2 #=> "This is example method one"
```

What happens is that the alias is defined at runtime, so anyone who depends on a re-defined version of the original method gets different behavior for the aliased method.

With `forwardable