diff --git a/include/base.h b/include/base.h
index 24b7329..3b7a243 100644
--- a/include/base.h
+++ b/include/base.h
@@ -92,5 +92,5 @@ static inline char *read_file(char *filename)
 #define WEST   1 // - x  cyan
 #define ZENITH 2 // + y  vert
 #define NADIR  3 // - y  magenta
-#define SOUTH  4 // - z  jaune
-#define NORTH  5 // + z  bleu
+#define SOUTH  4 // + z  bleu
+#define NORTH  5 // - z  jaune
diff --git a/src/graphics/arrows.c b/src/graphics/arrows.c
index 3dc2d7c..5ad6c0d 100644
--- a/src/graphics/arrows.c
+++ b/src/graphics/arrows.c
@@ -37,6 +37,8 @@ int write_one_arrow_vertex (int space_X_int, int space_Y_int, int space_Z_int,
      int weight, int site, int arrow_x, int arrow_y, int arrow_z, int print)
 {
 
+    printf("In write_one_arrow_vertex()  site = %d\n", site);
+
     float max = fmax(space_X_int, space_Y_int);
           max = fmax(max, space_Z_int);
 
@@ -71,12 +73,12 @@ int write_one_arrow_vertex (int space_X_int, int space_Y_int, int space_Z_int,
         graphics_write_color(0.6f, 0.1f, 0.7f);
         break;
     case SOUTH:
-        graphics_write_vertex (vx, vy, vz - (site % 2 - 1) * (1 / max) + (site % 2 - 1) * arrow_tip_padding, print);
-        graphics_write_color(1.0f, 1.0f, 0.0f);
+        graphics_write_vertex (vx, vy, vz - (site % 2 + 1) * (1 / max) + (site % 2 + 1) * arrow_tip_padding, print);
+        graphics_write_color(0.05f, 0.4f, 1.0f);
         break;
     case NORTH:
-        graphics_write_vertex (vx, vy, vz - (site % 2) * (1 / max) + (site % 2) * arrow_tip_padding, print);
-        graphics_write_color(0.05f, 0.4f, 1.0f);
+        graphics_write_vertex (vx, vy, vz - (site % 2 - 2) * (1 / max) + (site % 2 - 2) * arrow_tip_padding, print);
+        graphics_write_color(1.0f, 1.0f, 0.0f);
         break;
     default: break;
     }
diff --git a/src/graphics/graphics.c b/src/graphics/graphics.c
index 7bcf869..7b90af4 100644
--- a/src/graphics/graphics.c
+++ b/src/graphics/graphics.c
@@ -735,7 +735,7 @@ static inline int set_arrow (struct arrow_t *arrows_ptr, int arrows_nb, int spac
 void main_test_graphics (void)
 {
     srand(time(NULL)); int rand(void); void srand(unsigned int seed);
-    int randomize = 7, console = 0, arrows_nb = 0, space_X = 1, space_Y = 1, space_Z = 1;
+    int randomize = 5, console = 0, arrows_nb = 0, space_X = 1, space_Y = 1, space_Z = 1;
     if (randomize) {
         space_X = 1 + rand() % randomize;
         space_Y = 1 + rand() % randomize;
@@ -792,3 +792,4 @@ void main_test_graphics (void)
 
     free(arrows_ptr);               arrows_ptr = NULL;            arrows_nb = 0;
 }
+