solve(ANS,12).
choice([3,14,6,9],ANS),sum(ANS,12)
choice([3,14,6,9],ANS)
choice([14,6,9],ANS)
choice([6,9],ANS)
choice([9],ANS)
ANS=[0]
choice([ ],ANS)
ANS=[ ]
choice([H|T],[0|Y]):-choice(T,Y).
Y=[ ], ANS=[0|Y]
T=Y=[ ]
巻取り段階