ov.rb

class OV
  def vals
    ['a', 'b', 'c']
  end

  # this will make this work:
  # OV.new == 'a'
  # true
  # OV.new == 'b'
  # true
  # but not this:
  # 'b' == OV.new
  # false
  def ==(other)
    vals.include?(other)
  end

  # when this method is defined def ==() works THE OTHER WAY AROUND
  # so this will work:
  # 'a' == OV.new
  # true
  # 'b' == OV.new
  # true
  def to_str
  end
end