diff --git a/src/graphics/arrows.c b/src/graphics/arrows.c
index c46c9da..1a89c6f 100644
--- a/src/graphics/arrows.c
+++ b/src/graphics/arrows.c
@@ -165,49 +165,22 @@ void arrows_write_basis(long offset)
 }
 
 
-static void show_one_arrow_data_1(int offset_vertex, int offset_colors,
-                int space_X, int space_Y, int space_Z,
-                int weight, int site, int x, int y, int z)
-{
-    printf("offset_vertex = %d   offset_colors = %d   weight = %d    site = %d    x,y,z = (%d,%d,%d)\n",\
-           offset_vertex, offset_colors, weight, site, x, y, z);
-}
-
-static void show_one_arrow_data_2(int offset_vertex, int max, int uxi, int uyi, int uzi,
-                                  int ux, int uy, int uz, float vx, float vy, float vz)
-{
-    printf("offset_vertex = %d (x3 = %d)   max = %d\n\
-       xi =  %d           yi =  %d     zi =  %d\n\
-       ux = %d      uy =  %d     uz = %d\n\
-       vx = %6.3f       vy = %6.3f vz = %6.3f\n",\
-       offset_vertex, offset_vertex * 3, max, ux, uy, uz, vx, vy, vz);
-}
-
-
 /******************************************************************************/
 
 void write_one_arrow(int offset_vertex, int offset_colors, int offset_lines,
                      int space_X_int, int space_Y_int, int space_Z_int,
-                     int weight, int site, int x, int y, int z)
+                     int weight, int site, int arrow_x, int arrow_y, int arrow_z)
 {
-    //  show_one_arrow_data_1 (offset_vertex, offset_colors, space_X, space_Y, space_Z, weight, site, x, y, z);
-
     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 i = arrow_x, j = arrow_y, k = arrow_z;
 
-    int   ux = uxi, uy = uyi, uz = uzi;
-
-    float vx = (ux - 1) * (space_X / max) + (1.0f / max),
-          vy = (uy - 1) * (space_Y / max) + (1.0f / max),
-          vz = (uz - 1) * (space_Z / max) + (1.0f / max);
-
-    show_one_arrow_data_2 (offset_vertex, max,
-                        uxi, uyi, uzi, ux, uy, uz, vx, vy, vz);
+    float vx = (2 * i / space_X - 1) * space_X / max + (1 / max),
+          vy = (2 * j / space_Y - 1) * space_Y / max + (1 / max),
+          vz = (2 * k / space_Z - 1) * space_Z / max + (1 / max);
 
     //    arrow_basis_width donne la dimension de l'étoile centrale
     GLfloat arrow_basis_width = 0.3f * (1 / max),
@@ -263,7 +236,7 @@ void write_one_arrow(int offset_vertex, int offset_colors, int offset_lines,
     graphics_write_vertex (vx, vy, vz + (1 / max) - arrow_tip_padding);
     graphics_write_vertex (vx, vy, vz - (1 / max) + arrow_tip_padding);
     graphics_write_color(0.0f + nuance, 0.0f + nuance, 1.0f - nuance / 4);
-    graphics_write_color(1.0f - nuance / 3, 1.0f - nuance / 3, 0.0f + nuance);
+    graphics_write_color(1.0f - nuance / 4, 1.0f - nuance / 4, 0.0f + nuance);
 
     /* offset_vertex += 6; */
     /* offset_colors += 6; */