diff --git a/c/2024/6/guard_gallivant.c b/c/2024/6/guard_gallivant.c
index f528496..df39068 100644
--- a/c/2024/6/guard_gallivant.c
+++ b/c/2024/6/guard_gallivant.c
@@ -5,6 +5,8 @@
 
 #include "../../lib/aoc.h"
 
+#define MAX_LOOP_LENGTH 8000
+
 typedef enum Direction { RIGHT, UP, LEFT, DOWN } Direction;
 
 typedef struct Position {
@@ -18,6 +20,9 @@ typedef struct Game {
   int height;
   Position guard;
   Direction guard_direction;
+  Position guard_start;
+  Direction guard_start_direction;
+  int positions[10000];
   int position_count;
 } Game;
 
@@ -61,7 +66,7 @@ void turn_guard(Game *game) {
   game->guard_direction = new_direction;
 }
 
-void move_guard(Game *game) {
+void move_guard(Game *game, bool deface) {
   Position target;
   target.x = game->guard.x;
   target.y = game->guard.y;
@@ -82,9 +87,10 @@ void move_guard(Game *game) {
 
   if (position_has_obstacle(game, target)) turn_guard(game);
   else {
-    if (game->map[index_from_position(game, game->guard)] == '.') {
-      game->map[index_from_position(game, game->guard)] = 'X';
-      game->position_count++;
+    int index = index_from_position(game, game->guard);
+    if (deface && game->map[index] == '.') {
+      game->map[index] = 'X';
+      game->positions[game->position_count++] = index;
     }
       
     game->guard.x = target.x;
@@ -93,9 +99,10 @@ void move_guard(Game *game) {
 }
 
 int main() {
-  char *line;
+  char *dirty_map = aoc_read_input();
+
   Game game;
-  game.map = aoc_read_input();
+  game.map = dirty_map;
   game.width = strchr(game.map, '\n') - game.map + 1;
   game.height = strlen(game.map) / game.width;
   game.position_count = 0;
@@ -104,15 +111,57 @@ int main() {
       game.map[i] = '.';
       game.guard = position_from_index(&game, i);
       game.guard_direction = UP;
+      game.guard_start = game.guard;
+      game.guard_start_direction = game.guard_direction;
       break;
     }
   }
+  char *clean_map = malloc(strlen(dirty_map) + 1);
+  strcpy(clean_map, dirty_map);
+
+  Game time_travel_game;
+  time_travel_game.map = clean_map;
+  time_travel_game.width = game.width;
+  time_travel_game.height = game.height;
+  time_travel_game.position_count = 0;
+  time_travel_game.guard = game.guard;
+  time_travel_game.guard_direction = game.guard_direction;
+  time_travel_game.guard_start = game.guard;
+  time_travel_game.guard_start_direction = game.guard_direction;
 
   while (guard_inbounds(&game)) {
-    move_guard(&game);
+    move_guard(&game, true);
+  }
+  printf("Part 1: %d\n", game.position_count);
+
+  int loop_count = 0;
+  for (int i = 0; i < game.position_count; i++) {
+    time_travel_game.map[game.positions[i]] = '#';
+    int gsx = time_travel_game.guard_start.x;
+    int gsy = time_travel_game.guard_start.y;
+    int gsd = time_travel_game.guard_start_direction;
+    time_travel_game.guard = time_travel_game.guard_start;
+    time_travel_game.guard_direction = time_travel_game.guard_start_direction;
+    int j = 0;
+    while (guard_inbounds(&time_travel_game)) {
+      move_guard(&time_travel_game, false);
+      if (time_travel_game.guard.x == gsx &&
+	  time_travel_game.guard.y == gsy &&
+	  time_travel_game.guard_direction == gsd) {
+	loop_count++;
+	break;
+      }
+      j++;
+      if (j % MAX_LOOP_LENGTH == 0) {
+	gsx = time_travel_game.guard.x;
+	gsy = time_travel_game.guard.y;
+	gsd = time_travel_game.guard_direction;
+      }
+    }
+    time_travel_game.map[game.positions[i]] = '.';
   }
 
-  printf("Part 1: %d\n", game.position_count);
+  printf("Part 2: %d\n", loop_count);
 
   aoc_free();
   return 0;