Just run advent.rkt in drracket, the development environment for Racket,
a wel-known dialct of Scheme.

advent.rkt requires game.rkt, so have both of them
in the same current directory.

The code occsionally uses the parendown package; use the drracket menu
item for installing packages to install it.
NOTE:There are very few places where the parendown is used;
instead, you can replace things like ( fff hhh #/ eee ggg) by
(fff hhh ( eee ggg )). parendown is just a syntax hack to reduce
close-parnthesis pileups.

The game is probaby not worth playing.
You can respone to the doorbell,
but the game ends before you get to open the door.
I got sick an didn't even manage to put all the pieces I wrote together.
(I'm better now -- no need for get well cards)

-- hendrik
)