As for the second part of the class, we discussed various methods of
counting (review), and then a special method of counting, which I'll
illustrate with a couple of other examples. In class (and in the Day 09 page), we showed how to use a ternary tree
to do the counting. The method is described there. But let me provide a
few more examples, which we did on the board. So I'll record the
process of going through a few more examples of "counting by
partition".
It turns out that it's closely related to the "Fraudini trick" (as
pointed out during the class video). I'll point that out during these
examples, too -- but it will pay to have your cards at the ready.
