diff --git a/Plague.g1a b/Plague.g1a
index fefbe92..8fd3ccb 100644
Binary files a/Plague.g1a and b/Plague.g1a differ
diff --git a/src/core.h b/src/core.h
index 196644d..66956ed 100644
--- a/src/core.h
+++ b/src/core.h
@@ -14,8 +14,9 @@
 // Number of planes on screen
 #define NB_PLANES 5
 
-struct grid {
-    
+struct grid
+{    
+    // 64, 128
     int height, width;
 
     // Use grid.data[i + j * grid.width] instead of grid.data[i][j]
diff --git a/src/display_engine.c b/src/display_engine.c
index b511339..e58d63f 100644
--- a/src/display_engine.c
+++ b/src/display_engine.c
@@ -8,7 +8,7 @@
 void display_background(const int background)
 {
     extern const bopti_image_t img_bground;
-    dsubimage(0, 0, &img_bground, 0, 65 * (background - 1), 128, 64, DIMAGE_NONE);
+    if (background != 6) dsubimage(0, 0, &img_bground, 0, 65 * (background - 1), 128, 64, DIMAGE_NONE);
 }
 
 
@@ -29,7 +29,7 @@ void display_foreground(const int background, const struct game *current_game)
             {
                 for (int j = 0; j < current_game->grid.height; j ++)
                 {
-                    if (current_game->grid.data[i + j * current_game->grid.width] != 0 && world[i][j] != 0) dpixel(i, j, C_BLACK);
+                    if (current_game->grid.data[i + j * current_game->grid.width] == 1 && world[i][j] != 0) dpixel(i, j, C_BLACK);
                 }
             }
 
@@ -47,7 +47,7 @@ void display_foreground(const int background, const struct game *current_game)
             {
                 for (int j = 0; j < 50; j ++)
                 {
-                    if (current_game->grid.data[i + j * current_game->grid.width] != 0 && world[i][j] != 0) dpixel(i, j, C_BLACK);
+                    if (current_game->grid.data[i + j * current_game->grid.width] == 1 && world[i][j] != 0) dpixel(i, j, C_BLACK);
                 }
             }
 
diff --git a/src/epidemic_engine.c b/src/epidemic_engine.c
index 93c8790..d15b50b 100644
--- a/src/epidemic_engine.c
+++ b/src/epidemic_engine.c
@@ -2,14 +2,10 @@
 #include "epidemic_engine.h"
 
 
-#include <gint/keyboard.h>
-#include <gint/display.h>
-
-
 int grid_get(const struct grid epidemic_grid, const int i, const int j)
 {
-    if (i < 0 || j < 0 || i >= epidemic_grid.width || j >= epidemic_grid.height) return epidemic_grid.data[i + j * epidemic_grid.width];
-    return 0;
+    if (i < 0 || j < 0 || i >= epidemic_grid.width || j >= epidemic_grid.height) return 0;
+    else return epidemic_grid.data[i + j * epidemic_grid.width];
 }
 
 
@@ -18,43 +14,41 @@ bool can_become_infected(const struct grid epidemic_grid, const int mutations_se
     extern const unsigned int world[64][128];
 
     // In case of water, low or high temperature
-    if (world[j][i] == 0 && mutations_selected[2] != 3) return false;
+    /*if (world[j][i] == 0 && mutations_selected[2] != 3) return false;
     if (world[j][i] == 1 && mutations_selected[1] != 0 && mutations_selected[1] != 4) return false;
-    if (world[j][i] == 3 && mutations_selected[1] != 1 && mutations_selected[1] != 4) return false;
+    if (world[j][i] == 3 && mutations_selected[1] != 1 && mutations_selected[1] != 4) return false;*/
     
     // Test cases around
     return grid_get(epidemic_grid, i - 1, j) == 1 || grid_get(epidemic_grid, i + 1, j) == 1 || grid_get(epidemic_grid, i, j - 1) == 1 || grid_get(epidemic_grid, i, j + 1) == 1;
 }
 
 
-bool bernoulli(const float p)
+bool bernoulli(const int p)
 {
-    return (rand() / 2147483647) <= p;
+    return (rand() % 101) <= p;
 }
 
 
 void epidemic_simulation(struct game *current_game)
 {
     srand(15510);
-    double contagion_rate = current_game->contagion / 100;
-    double lethality_rate = current_game->lethality / 100;
-    double healed_rate =  current_game->research / current_game->limit;
 
-    dclear(C_WHITE);
-    dprint(5, 5, C_BLACK, "HR:%lf", healed_rate);
-    dupdate();
-    getkey();
+    int healed_rate =  100 * (current_game->research / current_game->limit);
 
     for (int i = 0; i < current_game->grid.width; i ++)
     {
         for (int j = 0; j < current_game->grid.height; j ++)
         {
+            current_game->grid.data[i + j * current_game->grid.width] = 1;
+        
+            /*
             switch (current_game->grid.data[i + j * current_game->grid.width])
             {
                 // Healthy
-                case 0: 
-                    if (can_become_infected(current_game->grid, current_game->mutations_selected, i, j) 
-                    && bernoulli(contagion_rate))
+                case 0:
+
+                    // Become infected
+                    if (can_become_infected(current_game->grid, current_game->mutations_selected, i, j) && bernoulli(current_game->contagion))
                     {
                         current_game->grid.data[i + j * current_game->grid.width] = 1;
                         current_game->humans[0] --;
@@ -74,15 +68,15 @@ void epidemic_simulation(struct game *current_game)
                     }
 
                     // Become dead
-                    else if (bernoulli(lethality_rate))
+                    else if (bernoulli(current_game->lethality))
                     {
                         current_game->grid.data[i + j * current_game->grid.width] = 3;
                         current_game->humans[1] --;
                         current_game->humans[3] ++;
                     }
                     break;
-            }
+            }*/
 
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/epidemic_engine.h b/src/epidemic_engine.h
index b217ff5..a2cdd80 100644
--- a/src/epidemic_engine.h
+++ b/src/epidemic_engine.h
@@ -10,7 +10,7 @@
 bool can_become_infected(const struct grid epidemic_grid, const int mutations_selected[3], const int i, const int j);
 
 // bernoulli : simulate a random event
-bool bernoulli(const float p);
+bool bernoulli(const int p);
 
 // epidemic_simulation : simulate the propagation of the virus
 void epidemic_simulation(struct game *current_game);
diff --git a/src/main.c b/src/main.c
index a59da4b..bbc5f77 100644
--- a/src/main.c
+++ b/src/main.c
@@ -67,6 +67,12 @@ int main(void)
     /* allocate memory */
     current_game.grid.data = calloc(current_game.grid.width * current_game.grid.height, sizeof(uint8_t));
 
+    if (current_game.grid.data == NULL)
+    {
+        const char *msg[5] = {"CALLOC", "FAILED", "", "", ""};
+        message(msg);
+    }
+
     current_game.grid.data[95 + 20 * current_game.grid.width] = 1;
     current_game.humans[0] = (current_game.grid.width * current_game.grid.height) - 1;