Read the Feigenbaum Plot Article article that you got at the end of class today. In particular, pay attention to the converging ratio of gaps between bifurcation points, and the second page that discussing the ordering of cycles. You may also want to check out this Numberphile video about this same topic.
Also, keep playing with the Feigenbaum Plot applet! Remember that you’ll need to use a Java-permitting internet browser in order to view it.