class InfiniteArray < Array
  def initialize(value)
    super(1, value)
  end
  def [](index)
    self.first
  end
end


irb(main):011:0> a = InfiniteArray.new('str')
=> ["str"]
irb(main):012:0> a[999999]
=> "str"
irb(main):013:0> a.first
=> "str"
irb(main):014:0> a.last
=> "str"