gistfile1.txt

module Other
end

module Foo
  module Other
  end

  module Bar
    def x
      Other # Looked up to Foo::Other
    end
  end
end


module Foo::Bar
  def x
    Other # Looked up to ::Other
  end
end

gistfile2.txt

module Foo
  module Bar
    def x
      mutated
    end
  end
end