diff --git a/pl/04.1.pl b/pl/04.1.pl
new file mode 100644
index 0000000..f35d756
--- /dev/null
+++ b/pl/04.1.pl
@@ -0,0 +1,135 @@
+read_file(Stream, []) :-
+    at_end_of_stream(Stream).
+read_file(Stream, [X|L]) :-
+    \+ at_end_of_stream(Stream),
+    read_line_to_codes(Stream, C),
+    string_chars(X, C),
+    read_file(Stream, L).
+
+split1([], [], []).
+split1([""|As], [], As). % starts with "" -> [], seq end
+split1([A|As], [A|Bs], X) :-
+    A \= "",
+    split1(As, Bs, X).
+
+split2([], []).
+split2([A|As], [B|Bs]) :-
+    split1([A|As], B, C),
+    split2(C, Bs).
+
+remove_x(_, [], []).
+remove_x(X, [X|As], Bs) :-
+    remove_x(X, As, Bs).
+remove_x(X, [A|As], [A|Bs]) :-
+    A \= X,
+    remove_x(X, As, Bs).
+
+numbers_strings([], []).
+numbers_strings([A|As], [B|Bs]) :-
+    number_string(A, B),
+    numbers_strings(As, Bs).
+
+strings_board([], []).
+strings_board([A|As], [B|Bs]) :-
+    split_string(A, " ", "", C),
+    remove_x("", C, D),
+    numbers_strings(B, D),
+    strings_board(As, Bs).
+
+stringss_boards([], []).
+stringss_boards([A|As], [B|Bs]) :-
+    strings_board(A, B),
+    stringss_boards(As, Bs).
+
+parse_boards(L, A) :-
+    split2(L, B),
+    remove_x([], B, C),
+    stringss_boards(C, A).
+
+parse_file([X|L], N, B) :-
+    split_string(X, ",", "", A),
+    numbers_strings(N, A),
+    parse_boards(L, B).
+
+main :-
+    open('../input/04', read, Stream),
+    read_file(Stream, Lines), !,
+    close(Stream),
+
+    parse_file(Lines, A, B),
+    step_first_board_win(A, B, C),
+    print(C).
+
+mark_nums_row(_, [], []).
+mark_nums_row(N, [R|Rs], [1|Xs]) :-
+    append([_, [R], _], N),
+    mark_nums_row(N, Rs, Xs).
+mark_nums_row(N, [R|Rs], [0|Xs]) :-
+    \+ append([_, [R], _], N),
+    mark_nums_row(N, Rs, Xs).
+
+mark_nums_board(_, [], []).
+mark_nums_board(N, [B|Bs], [C|Cs]) :-
+    mark_nums_row(N, B, C),
+    mark_nums_board(N, Bs, Cs).
+
+rows_win([R|Rs]) :-
+    (R = [1,1,1,1,1]; rows_win(Rs)).
+
+transpose([[]|_], []).
+transpose(A, [B|Bs]) :-
+    first_column(A, B, C),
+    transpose(C, Bs).
+
+first_column([], [], []).
+first_column([[B|C]|As], [B|Bs], [C|Cs]) :-
+    first_column(As, Bs, Cs).
+
+marked_board_win(B) :-
+    transpose(B, T),
+    (rows_win(B); rows_win(T)).
+
+unmarked_row_sum([], [], 0).
+unmarked_row_sum([_|As], [1|Ms], C) :-
+    unmarked_row_sum(As, Ms, C).
+unmarked_row_sum([A|As], [0|Ms], C) :-
+    unmarked_row_sum(As, Ms, C1),
+    C is A + C1.
+
+unmarked_board_sum([], [], 0).
+unmarked_board_sum([A|As], [B|Bs], C) :-
+    unmarked_row_sum(A, B, C1),
+    unmarked_board_sum(As, Bs, C2),
+    C is C1 + C2.
+
+last_num([R], R).
+last_num([_|Rs], X) :-
+    last_num(Rs, X).
+
+board_win(N, B, X) :-
+    mark_nums_board(N, B, C),
+    marked_board_win(C),
+    unmarked_board_sum(B, C, Z),
+    last_num(N, Y),
+    X is Y * Z.
+
+first_board_win(N, [B|_], C) :-
+    board_win(N, B, C).
+
+first_board_win(N, [B|Bs], C) :-
+    \+ board_win(N, B, _),
+    first_board_win(N, Bs, C).
+
+step_first_board_win([A|As], [], B, C) :-
+    step_first_board_win(As, [A], B, C).
+step_first_board_win([_|_], [N|Ns], B, C) :-
+    first_board_win([N|Ns], B, C).
+step_first_board_win([A|As], [N|Ns], B, C) :-
+    \+ first_board_win([N|Ns], B, _),
+    append([N|Ns], [A], D),
+    step_first_board_win(As, D, B, C).
+step_first_board_win([], N, B, C) :-
+    first_board_win(N, B, C).
+
+step_first_board_win(N, B, C) :-
+    step_first_board_win(N, [], B, C).
diff --git a/pl/04.2.pl b/pl/04.2.pl
new file mode 100644
index 0000000..656bbf2
--- /dev/null
+++ b/pl/04.2.pl
@@ -0,0 +1,141 @@
+read_file(Stream, []) :-
+    at_end_of_stream(Stream).
+read_file(Stream, [X|L]) :-
+    \+ at_end_of_stream(Stream),
+    read_line_to_codes(Stream, C),
+    string_chars(X, C),
+    read_file(Stream, L).
+
+split1([], [], []).
+split1([""|As], [], As). % starts with "" -> [], seq end
+split1([A|As], [A|Bs], X) :-
+    A \= "",
+    split1(As, Bs, X).
+
+split2([], []).
+split2([A|As], [B|Bs]) :-
+    split1([A|As], B, C),
+    split2(C, Bs).
+
+remove_x(_, [], []).
+remove_x(X, [X|As], Bs) :-
+    remove_x(X, As, Bs).
+remove_x(X, [A|As], [A|Bs]) :-
+    A \= X,
+    remove_x(X, As, Bs).
+
+numbers_strings([], []).
+numbers_strings([A|As], [B|Bs]) :-
+    number_string(A, B),
+    numbers_strings(As, Bs).
+
+strings_board([], []).
+strings_board([A|As], [B|Bs]) :-
+    split_string(A, " ", "", C),
+    remove_x("", C, D),
+    numbers_strings(B, D),
+    strings_board(As, Bs).
+
+stringss_boards([], []).
+stringss_boards([A|As], [B|Bs]) :-
+    strings_board(A, B),
+    stringss_boards(As, Bs).
+
+parse_boards(L, A) :-
+    split2(L, B),
+    remove_x([], B, C),
+    stringss_boards(C, A).
+
+parse_file([X|L], N, B) :-
+    split_string(X, ",", "", A),
+    numbers_strings(N, A),
+    parse_boards(L, B).
+
+main :-
+    open('../input/04', read, Stream),
+    read_file(Stream, Lines), !,
+    close(Stream),
+
+    parse_file(Lines, A, B),
+    solve(A, B, C),
+    print(C).
+
+mark_nums_row(_, [], []).
+mark_nums_row(N, [R|Rs], [1|Xs]) :-
+    append([_, [R], _], N),
+    mark_nums_row(N, Rs, Xs).
+mark_nums_row(N, [R|Rs], [0|Xs]) :-
+    \+ append([_, [R], _], N),
+    mark_nums_row(N, Rs, Xs).
+
+mark_nums_board(_, [], []).
+mark_nums_board(N, [B|Bs], [C|Cs]) :-
+    mark_nums_row(N, B, C),
+    mark_nums_board(N, Bs, Cs).
+
+rows_win([R|Rs]) :-
+    (R = [1,1,1,1,1]; rows_win(Rs)).
+
+transpose([[]|_], []).
+transpose(A, [B|Bs]) :-
+    first_column(A, B, C),
+    transpose(C, Bs).
+
+first_column([], [], []).
+first_column([[B|C]|As], [B|Bs], [C|Cs]) :-
+    first_column(As, Bs, Cs).
+
+marked_board_win(B) :-
+    rows_win(B).
+marked_board_win(B) :-
+    transpose(B, T),
+    rows_win(T).
+
+unmarked_row_sum([], [], 0).
+unmarked_row_sum([_|As], [1|Ms], C) :-
+    unmarked_row_sum(As, Ms, C).
+unmarked_row_sum([A|As], [0|Ms], C) :-
+    unmarked_row_sum(As, Ms, C1),
+    C is A + C1.
+
+unmarked_board_sum([], [], 0).
+unmarked_board_sum([A|As], [B|Bs], C) :-
+    unmarked_row_sum(A, B, C1),
+    unmarked_board_sum(As, Bs, C2),
+    C is C1 + C2.
+
+last_num([R], R).
+last_num([_|Rs], X) :-
+    last_num(Rs, X).
+
+board_win(N, B, X) :-
+    mark_nums_board(N, B, C),
+    marked_board_win(C),
+    unmarked_board_sum(B, C, Z),
+    last_num(N, Y),
+    X is Y * Z.
+
+win_order(_, [], [], []).
+win_order(N, [B|Bs], C, [B|Rs]) :-
+    \+ board_win(N, B, _),
+    win_order(N, Bs, C, Rs).
+win_order(N, [B|Bs], [C|Cs], R) :-
+    board_win(N, B, C),
+    win_order(N, Bs, Cs, R).
+
+step_win_order(N, B, C) :-
+    step_win_order(N, [], B, C).
+step_win_order(_, _, [], []).
+step_win_order([A|As], [], B, C) :-
+    step_win_order(As, [A], B, C).
+step_win_order([A|As], [N|Ns], B, C) :-
+    win_order([N|Ns], B, C0, R),
+    append([N|Ns], [A], D),
+    step_win_order(As, D, R, C1),
+    append(C0, C1, C).
+step_win_order([], N, B, C) :-
+    win_order(N, B, C, _).
+
+solve(N, B, C) :-
+    step_win_order(N, B, D),
+    last_num(D, C).