2:16% irb -r ./fsq.rb
irb(main):001:0> q = FixedSizeQueue.new(3)
=> #<FixedSizeQueue:0x9317c6c @max_size=3, @items=[]>
irb(main):002:0> q.push 2
=> nil
irb(main):003:0> q.push 3
=> nil
irb(main):004:0> q.push 5
=> nil
irb(main):005:0> q
=> #<FixedSizeQueue:0x9317c6c @max_size=3, @items=[2, 3, 5]>
irb(main):006:0> q.push 7
=> 2
irb(main):007:0> q
=> #<FixedSizeQueue:0x9317c6c @max_size=3, @items=[3, 5, 7]>
irb(main):009:0> FixedSizeQueue.instance_methods(false)
=> [:pop, :push]