#from http://pragmaticprogrammer.com/titles/ruby/code/smp383.html  
# comments added

# equivalent to pr382.rb

  a = "hello"
  b = a.dup
  def a.to_s                               # adds a class to object a  
    "The value is '#{self}'"
  end
  def a.two_times                    # uses the same virtual class
    self + self
  end
  
  p a.to_s
  p a.two_times
  p b.to_s