Overriding methods (cont'd)

 1 class Array
 2   override_method(:concat) do
 3     def concat(*arrays)
 4       arrays.each { |array| super(array) }
 5     end
 6   end
 7 end
 8 
 9 a = [1, 2, 3]
10 a.concat([1], [2], [3, 4])
11 p a #=> [1, 2, 3, 1, 2, 3, 4]