Design History
Screen shot 1
Screen shot 2
Up to next event >= floor(lowest chosen rank)
Here we have the first two screen shots describing the design history.  The third one was the final screen shot.  Notice that the second diagram include relationships and classes drawn after the significant event and before the next agent since the lowest ranking chosen was that of an agent.

If we asked to see the three most significant screen shots showing the design history, we would see the two screen shots displayed here as well as the final screen shot.