diff --git a/prolog/day2.pl b/prolog/day2.pl
new file mode 100644
index 0000000..1790b2a
--- /dev/null
+++ b/prolog/day2.pl
@@ -0,0 +1,35 @@
+/**/
+fib(0, [0]).
+fib(1, [1,0]).
+fib(N, [R, X, Y | Zs]) :-
+	N > 1,
+	N1 is N - 1,
+	fib(N1, [X, Y | Zs]),
+	R is X + Y.
+
+% wrong naive impl
+reverse([], []).
+reverse([x], [x]).
+reverse([Head|Tail], [RNew, Head]) :-
+	reverse(Tail, RNew).
+
+accrev([H|T], Acc, R) :-
+	accrev(T, [H|Acc], R).
+accrev([], R, R).
+
+rev(L, R) :- accrev(L, [], R).
+
+smol([S], S).
+smol([H|T], S) :-
+	smol(T, Snew),
+	Snew < H -> S is Snew; S is H.
+
+% not working
+accsortt([], Acc, Acc).
+accsortt([H1 | T], Acc, R) :-
+	H2 | T,
+	H1 < H2
+	-> accsortt(T, [H1, H2 | Acc], R);
+	accsortt(T, [H2, H1 | Acc], R).
+
+sortt(L, R) :- accsortt(L, [], R).