$ irb22
irb> load "rotcev_rb.rb"
=> true
irb> foo = Rotcev.new
=> []
irb> foo = foo.put 1
=> [1]
irb> bar = foo.put 2
=> [2, 1]
irb> baz = bar.put 3
=> [3, 2, 1]
irb> foo
=> [1]
irb> bar
=> [2, 1]
irb> baz
=> [3, 2, 1]
irb> quux = bar.put 4
=> [4, 2, 1]
irb> bar
=> [2, 1]
irb> baz
=> [3, 2, 1]
