gistfile1.rb

class Puzzle
  attr_accessor :field
  
  def initialize
    self.field = true
  end
    
  def run
    puts field.inspect            # => true
    if false
      field = "NEVER SET"
    end    
    puts field.inspect            # => ?   << ** this is TRUE
  end
end
 
what_is_run = Puzzle.new.run
puts what_is_run   # => nil

#######################

class Puzzle
  attr_accessor :field
  
  def initialize
    self.field = true
  end
    
  def run
    puts field.inspect            # => true
    if false
      field = "NEVER SET"
    end    
    puts field.inspect            
    field   # ADDED
  end
end
 
what_is_run = Puzzle.new.run
puts what_is_run   # => TRUE