diff --git a/src/graphics/arrows.c b/src/graphics/arrows.c
index ddb02fc..bc099e7 100644
--- a/src/graphics/arrows.c
+++ b/src/graphics/arrows.c
@@ -173,44 +173,48 @@ static void show_one_arrow_data_1(int offset_vertex, int offset_colors,
            offset_vertex, offset_colors, weight, site, x, y, z);
 }
 
-static void show_one_arrow_data_2(int offset_vertex, int offset_colors,
-                float max, float base, float tip, float ux, float uy, float uz, float vx, float vy, float vz)
+static void show_one_arrow_data_2(int offset_vertex, float max, int uxi, int uyi, int uzi,
+                                  float ux, float uy, float uz, float vx, float vy, float vz)
 {
-    printf("offset_vertex = %d   max = %8.5f   base = %8.5f   tip = %8.5f\n\
-       ux = %8.5f   uy = %8.5f   uz = %8.5f\n       vx = %8.5f   vy = %8.5f   vz = %8.5f\n",\
-       offset_vertex, max, base, tip, ux, uy, uz, vx, vy, vz);
+    printf("offset_vertex = %d   max = %8.5f\n\
+       xi =   %6d   yi =   %6d   zi =   %6d\n\
+       ux = %8.5f   uy = %8.5f   uz = %8.5f\n\
+       vx = %8.5f   vy = %8.5f   vz = %8.5f\n",\
+       offset_vertex, max, ux, uy, uz, vx, vy, vz);
 }
 
 
 /******************************************************************************/
 
 void write_one_arrow(int offset_vertex, int offset_colors, int offset_lines,
-                     int space_X, int space_Y, int space_Z,
+                     int space_X_int, int space_Y_int, int space_Z_int,
                      int weight, int site, int x, int y, int z)
 {
     //  show_one_arrow_data_1 (offset_vertex, offset_colors, space_X, space_Y, space_Z, weight, site, x, y, z);
 
-    float nuance = 0.24f,
-          max = fmax(space_X, space_Y);
+    float space_X = space_X_int, space_Y = space_Y_int, space_Z = space_Z_int;
+    float max = fmax(space_X, space_Y);
           max = fmax(max, space_Z);
 
+    int   uxi = (2 * x) / space_X_int,
+          uyi = (2 * y) / space_Y_int,
+          uzi = (2 * z) / space_Z_int;
+
+    float ux = uxi, uy = uyi, uz = uzi;
+
+    float vx = (ux - 1.0f) * (space_X / max) + (1.0f / max),
+          vy = (uy - 1.0f) * (space_Y / max) + (1.0f / max),
+          vz = (uz - 1.0f) * (space_Z / max) + (1.0f / max);
+
+    show_one_arrow_data_2 (offset_vertex, max,
+                        uxi, uyi, uzi, ux, uy, uz, vx, vy, vz);
+
     //    arrow_basis_width donne la dimension de l'étoile centrale
     float arrow_basis_width = 0.3f * (1 / max),
 
     //    décale légèrement les pointes des flèches
     //    pour qu'elles n'aillent pas jusqu'aux faces des cubes
-          arrow_tip_padding = 0.1 * (1 / max),
-
-          ux = (2 * x) / space_X,
-          uy = (2 * y) / space_Y,
-          uz = (2 * z) / space_Z;
-
-    float vx = (ux - 1) * (space_X / max) + (1 / max),
-          vy = (uy - 1) * (space_Y / max) + (1 / max),
-          vz = (uz - 1) * (space_Z / max) + (1 / max);
-
-    show_one_arrow_data_2 (offset_vertex, offset_colors, max,
-                        ux, uy, uz, vx, vy, vz, arrow_basis_width, arrow_tip_padding);
+          arrow_tip_padding = 0.1 * (1 / max);
 
     //  X - X  axis - central star (basis)
     graphics_write_vertex(vx + arrow_basis_width, vy, vz);
@@ -241,6 +245,7 @@ void write_one_arrow(int offset_vertex, int offset_colors, int offset_lines,
 
 
 
+    float nuance = 0.24f;
 
     //  X - X  (EAST - WEST) axis - arrows tips  (red - green)
     graphics_write_vertex (vx + (1 / max) - arrow_tip_padding, vy, vz);