[Taken from Schoenfeld p. 268-9 with additions by Stephanie Wilcox.]
Consider the following magical configuration. In how many ways can you read the word "ABRACADABRA?"
A B B R R R A A A A C C C C C A A A A A A D D D D D A A A A B B B R R A
Is this similar to any problems we have done before? If so, which ones and how is it similar to the other problems? Is there a way to mathematically figure this problem without working it out by hand?