1. (cave/maze) 7 pts
   1 pt create-cave
   1 pt connect-caves

   6 pt create-player
        1  pt creating a message-handling function with local state
        1  pt 'what and 'where
        .5 pts 'show-next-exit
        .5 pts 'go!
        1  pt 'left and 'right
        1  pt 'switch-left and 'switch-right

        (-3 pts if doesn't handle local state in right scope)

   For doing more, may get points back missed above, although cannot get points
   back for missing big concepts, especially the overall structure of 
   create-player.
   Maximum of 2 points back for lots of really neat additional stuff.

2. 3 pts extra credit

   I don't see an easy way to subdivide the points, since it's pretty easy 
   with the supplied code.

   Doesn't matter if they use a vector of size 150 or 151 (ignoring index 0).