test3.pl

cone([o,o,o], 0).
cone(R, 1) :- select(x, R, [o,o]).
cone(R, 2) :- select(o, R, [x,x]).
cone([x,x,x], 3).

match([_,_], []).
match([A,B,C|R], [M|RM]) :- cone([A,B,C],M), match([B,C|R], RM).

mines(Count, Mines) :- same_length(Count, Mines), append([[o],Mines,[o]], M), match(M, Count).

table(T) :- T =
    [1 : [i],
     4 : [i, v], 5 : [v],
     9 : [i, x], 10 : [x],
     40 : [x, l], 50 : [l],
     90 : [x, c], 100 : [c],
     400 : [c, d], 500 : [d],
     900 : [c, m], 1000 : [m],
     10_000 : [err]].

roman(0, []).
roman(N, L) :- N in 1..3999, table(T),
    nextto(V : P, V1 : _, T), V #=< N, N #< V1,
    N1 #= N - V, append(P, L1, L), roman(N1, L1).