diff --git a/main.pl b/main.pl
index 6eb91e3..11d21ee 100644
--- a/main.pl
+++ b/main.pl
@@ -65,11 +65,11 @@ main_diagonal([Row|Rows], Column, [D|Ds]) :-
 % 
 % Holds when the variables in the list `Vars` can be unified 
 all_same([Var|Vars]) :-
- all_same(Var, Vars).
+  all_same(Var, Vars).
 
 all_same(Var, [Var]).
 all_same(Var, [Var|Vars]) :-
- all_same(Var, Vars).
+  all_same(Var, Vars).
 
 
 %% valid(+Row)