lib/metro/scene.rb
def after(ticks,&block)
      tick = OnUpdateOperation.new interval: ticks, context: self
      tick.on_complete(&block)
      enqueue tick
    end
def after(ticks,&block)
      tick = OnUpdateOperation.new interval: ticks, context: self
      tick.on_complete(&block)
      enqueue tick
    end
Perform an operation after the specified interval.

     class ExampleScene

       draws :player

       def update
         if player.is_dead?
           after 2.seconds do
             transition_to :game_over
           end
         end
       end

     end