I think the lesson was designed so that this was just obvious enough for people to realize it themselves as the demonstration progressed. Also, when done well,

I think the lesson was designed so that this was just obvious enough for people to realize it themselves as the demonstration progressed. Also, when done well, the teacher acts the part of the manager who keeps pushing people even as this realization spreads throughout the group. The meta-lesson is something that Deming emphasized over and over: Don't rate your workers based on the outcome of a random number generator.