4
6:-
7
8imm_west(r101,r103). 9imm_west(r103,r105).
10imm_west(r105,r107).
11imm_west(r107,r109).
12imm_west(r109,r111).
13imm_west(r131,r129).
14imm_west(r129,r127).
15imm_west(r127,r125).
16
17% imm_east(R1,R2) is true if room R1 is immediately east of room R2
18
19imm_east(R1,R2) <-
20 imm_west(R2,R1).
21
22% next_door(R1,R2) is true if room R1 is next door to room R2
23
24next_door(R1,R2) <-
25 imm_east(R1,R2).
26next_door(R1,R2) <-
27 imm_west(R1,R2).
28
29% two_doors_east(R1,R2) is true if room R1 is two doors east of room R2
30
31two_doors_east(R1,R2) <-
32 imm_east(R1,R) &
33 imm_east(R,R2).
34
35% west(R1,R2) is true if room R1 is somewhere west of room R2
36
37west(R1,R2) <-
38 imm_west(R1,R2).
39west(R1,R2) <-
40 imm_west(R1,R) &
41 west(R,R2).
42