(1)  ACHIEVABLE(west(m(s(s(s(0)))),c(s(s(s(0))))),boatonwest,east(m(0),c(0))).
(2)  -ACHIEVABLE(west(m(x),c(s(y))),boatonwest,east(m(z),c(w)))
  | ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(z),c(s(w)))).
(3)  -ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(z),c(s(w))))
  | ACHIEVABLE(west(m(x),c(s(y))),boatonwest,east(m(z),c(w))).
(4) -ACHIEVABLE(west(m(s(s(x))),c(y)),boatonwest,east(m(z),c(w)))
  | ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(s(s(z))),c(w))).
(5)  ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(s(s(z))),c(w)))
  | ACHIEVABLE(west(m(s(s(x))),c(y)),boatonwest,east(m(z),c(w))).
(6) -ACHIEVABLE(west(m(s(x)),c(s(y))),boatonwest,east(m(z),c(w)))
  | ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(s(z)),c(s(w)))).
(7) -ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(s(z)),c(s(w))))
  | ACHIEVABLE(west(m(s(x)),c(s(y))),boatonwest,east(m(z),c(w))).
ne missionary from west to east:
(8) -ACHIEVABLE(west(m(s(x)),c(y)),boatonwest,east(m(z),c(w)))
  | ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(s(z)),c(w))).
(9) -ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(s(z)),c(w)))
  | ACHIEVABLE(west(m(s(x)),c(y)),boatonwest,east(m(z),c(w))).
(10) -ACHIEVABLE(west(m(x),c(s(s(y)))),boatonwest,east(m(z),c(w)))
  | ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(z),c(s(s(w))))).
(11)  ACHIEVABLE(west(m(x),c(y)),boatoneast,east(m(z),c(s(s(w)))))
  | ACHIEVABLE(west(m(x),c(s(s(y)))),boatonwest,east(m(z),c(w))).
(12) -ACHIEVABLE(west(m(0),c(0)),x,east(m(s(s(s(0)))),c(s(s(s(0)))))).
(13)  ACHIEVABLE(west(m(s(x)),c(s(s(x)))),y,east(z,w)).
(14)  ACHIEVABLE(west(m(s(x)),c(s(s(s(x))))),y,east(z,w)).
(15)  ACHIEVABLE(west(x,y),z,east(m(s(w)),c(s(s(w))))).
(16)  ACHIEVABLE(west(x,y),z,east(m(s(w)),c(s(s(s(w)))))).