diff --git a/6.0s1.h b/6.0s1.h
index 6d637c7..ba18906 100644
--- a/6.0s1.h
+++ b/6.0s1.h
@@ -18,8 +18,8 @@ typedef char      s1_char;
 
 #   ifndef S1_6_0_H_IMPL
 
-#   include <stdio.h>
-#   include <stdlib.h>
+#       include <stdio.h>
+#       include <stdlib.h>
 
 // 1. assert 
 void s1_assert(int value, const char *reason, struct s1_location loc) {
@@ -58,10 +58,10 @@ void write_char(s1_char value, struct s1_location loc) {
     s1_assert(rc != EOF, "Error: write_char", loc);
 }
 
-#define write_int(value)      write_int(value, S1_LOC())
-#define write_long(value)     write_long(value, S1_LOC())
-#define write_double(value)   write_double(value, S1_LOC())
-#define write_char(value)     write_char(value, S1_LOC())
+#       define write_int(value)      write_int(value, S1_LOC())
+#       define write_long(value)     write_long(value, S1_LOC())
+#       define write_double(value)   write_double(value, S1_LOC())
+#       define write_char(value)     write_char(value, S1_LOC())
 
 s1_int read_int(struct s1_location loc) {
     s1_int value = 0;
@@ -106,11 +106,11 @@ void read_pnl(struct s1_location loc) {
 }
 
 
-#define read_int()      read_int(S1_LOC())
-#define read_long()     read_long(S1_LOC())
-#define read_double()   read_double(S1_LOC())
-#define read_char()     read_char(S1_LOC())
-#define read_pnl()      read_pnl(S1_LOC())
+#       define read_int()      read_int(S1_LOC())
+#       define read_long()     read_long(S1_LOC())
+#       define read_double()   read_double(S1_LOC())
+#       define read_char()     read_char(S1_LOC())
+#       define read_pnl()      read_pnl(S1_LOC())
 #   endif