#  First test problem
x:ducks
y:birds
z:creatures-with-legs
w:swimmers
Axy
Ayz
Ixw
c Iwz
#  Second test problem
Exy
Azx
Es-z
C Esy
x:human beings
y:frogs
z:U.S. Presidents
s:George Bushes
#
Acd
Abc
Aab
c Aad
#1
Acd
Abc
E-ba
c Aad
#2
Acd
Abc
Ea-b
c Aad
#3
Acd
Abc
A-b-a
c Aad
#4
Acd
A-cb
Eba
c Aad
#5
Acd
A-cb
Eab
c Aad
#6
Acd
A-cb
Aa-b
c Aad
#7
Acd
A-cb
Ab-a
c Aad
#8
Acd
E-cb
Aab
c Aad
#9
Acd
E-cb
E-ba
c Aad
#10
Acd
E-cb
Ea-b
c Aad
#11
Acd
E-cb
A-b-a
c Aad
#12
Acd
Eb-c
Aab
c Aad
#13
Acd
Eb-c
E-ba
c Aad
#14
Acd
Eb-c
Ea-b
c Aad
#15
Acd
Eb-c
A-b-a
c Aad
#16
Acd
A-bc
Eba
c Aad
#17
Acd
A-bc
Eab
c Aad
#18
Acd
A-bc
Aa-b
c Aad
#19
Acd
A-bc
Ab-a
c Aad
#20
Acd
A-c-b
Aab
c Aad
#21
Acd
A-c-b
E-ba
c Aad
#22
Acd
A-c-b
Ea-b
c Aad
#23
Acd
A-c-b
A-b-a
c Aad
#24
Acd
E-c-b
Eba
c Aad
#25
Acd
E-c-b
Eab
c Aad