This is a pretty sad game demo.
START: ROOM = "VALLEY|BROOK|GLADE"
CONT: IGNORE = ROOM
VALLEY: OUTPUT = "You are standing in a valley."
HILL: OUTPUT = "You are on top of a hill."
BROOK: OUTPUT = "You are by a brook."
GLADE: OUTPUT = "You are standing in a sun-dappled glade."
ROOM: OUTPUT = EOL
ROOM: DIR = CHOP INPUT
ROOM: IGNORE = DIR
ROOM: MASK = "VAPOURS"
N: CAT = "|N"
S: CAT = "|S"
E: CAT = "|E"
W: CAT = "|W"
ROOM: IGNORE = MASK
N: ROOM = "VALLEY|BROOK|GLADE"
S: ROOM = "HILL|BROOK|GLADE"
E: ROOM = "VALLEY|HILL|BROOK"
W: ROOM = "VALLEY|HILL|GLADE"
LASTLY: IGNORE = "START"