ah 4. A cleverer state space for this problem defines a "state" to be either the part of bottom that goes past the top, or vice versa. For example, if you have the dominoes D1-abb D2, D3- then the two strings {D1,02) obia and {D3}- anio can be consid- cred the same state, because in either case you have to "make up" a trailing "ab" on the bottom, and any sequence that can be added after {D1,D2} to solve the problem will work just as well when added after {D3). Construct an example of a sequence of dominoes whose state space, defined this way, has a cycle