diff --git a/include/arrows.h b/include/arrows.h
index 4ac83bd..c032fa4 100644
--- a/include/arrows.h
+++ b/include/arrows.h
@@ -38,9 +38,8 @@ typedef struct arrow_t {
     GLuint z;
 };
 
-int write_one_arrow_vertex (int offset_vertex,
-                    int space_X, int space_Y, int space_Z,
-                    int weight, int site, int x, int y, int z);
+int write_one_arrow_vertex (int space_X, int space_Y, int space_Z,
+                            int weight, int site, int x, int y, int z);
 
 int write_one_arrow_line(int offset_vertex);
 
diff --git a/src/graphics/arrows.c b/src/graphics/arrows.c
index f3fa332..f8baa3e 100644
--- a/src/graphics/arrows.c
+++ b/src/graphics/arrows.c
@@ -33,8 +33,7 @@
  *  Z - Z   =   NORTH  - SOUTH   =   bleu  - jaune
  */
 
-int write_one_arrow_vertex (int offset_vertex,
-                    int space_X_int, int space_Y_int, int space_Z_int,
+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)
 {
 
@@ -47,14 +46,11 @@ int write_one_arrow_vertex (int offset_vertex,
           vy = (2 * j / space_Y_int - 1) * space_Y_int / max + (1 / max),
           vz = (2 * k / space_Z_int - 1) * space_Z_int / max + (1 / max);
 
-    //  ici,  arrow_basis_width = 0   <>  Plus d'étoile centrale
-    GLfloat arrow_basis_width = 0;  //  (1 / max) / 5;
     graphics_write_vertex(vx, vy, vz);
     graphics_write_color(0.3f, 0.3f, 0.3f);
 
-
-    //    décale légèrement les pointes des flèches
-    //    pour qu'elles n'aillent pas jusqu'aux faces des cubes
+    //    réduit légèrement les longueurs des flèches
+    //    pour qu'elles s'arrêtent avant les faces des cubes
     GLfloat arrow_tip_padding = (1 / max) / 10;
 
     switch(site){
diff --git a/src/graphics/graphics.c b/src/graphics/graphics.c
index e6f1dea..f718245 100644
--- a/src/graphics/graphics.c
+++ b/src/graphics/graphics.c
@@ -133,8 +133,8 @@ void graphics_write_vertex (GLfloat x, GLfloat y, GLfloat z)
     buffer_vertex_origin[buffer_vertex_size + 1] = y;
     buffer_vertex_origin[buffer_vertex_size + 2] = z;
 
-    if (0) printf("In graphics_write_vertex() buffer_vertex_size = %2d > %2d (%6.3f,%6.3f,%6.3f)\n",\
-                  buffer_vertex_size, buffer_vertex_size + 3, x, y, z);
+    if (1) printf("In graphics_write_vertex() buffer_vertex_size => [%2d > %2d] (%6.3f,%6.3f,%6.3f)\n",\
+                  buffer_vertex_size + 0, buffer_vertex_size + 2, x, y, z);
 
     buffer_vertex_size += 3;
 }
@@ -177,8 +177,8 @@ void graphics_write_line (GLuint a, GLuint b)
     buffer_lines_origin[buffer_lines_size + 0] = a;
     buffer_lines_origin[buffer_lines_size + 1] = b;
 
-    if (0) printf("In graphics_write_line() buffer_lines_size = %2d > %2d\n",\
-                  buffer_lines_size, buffer_lines_size + 2);
+    if (1) printf("In graphics_write_line() buffer_lines_size => [%2d > %2d]\n",\
+                  buffer_lines_size + 0, buffer_lines_size + 1);
 
     buffer_lines_size += 2;
 }
@@ -582,12 +582,16 @@ static inline int create_arrow (int arrows_nb,
     arrows_ptr[arrows_nb].y = y;
     arrows_ptr[arrows_nb].z = z;
 
-    write_one_arrow_vertex(buffer_vertex_size,
-                           space_X, space_Y, space_Z,
+    /* if (1) printf("In create_arrow() buffer_vertex_size => [%2d > %2d] (%6.3f,%6.3f,%6.3f)\n",\ */
+    /*               buffer_vertex_size + 0, buffer_vertex_size + 2, x, y, z); */
+
+    write_one_arrow_vertex(space_X, space_Y, space_Z,
                            load, site, x, y, z);
     buffer_colors_size = buffer_vertex_size;
 
-    write_one_arrow_line (buffer_vertex_size);
+    /* write_one_arrow_line (buffer_vertex_size); */
+    /* cas (1,1,1)  graphics_write_line (9, 10);    graphics_write_line (10, 11); */
+    graphics_write_line (13, 14); graphics_write_line (14, 15);
 
     arrows_nb ++;
 
@@ -696,9 +700,9 @@ void  __attribute__((optimize("no-unroll-loops"))) main_test_graphics (void)
     void srand(unsigned int seed);  //    printf ("Valeur max : %d\n", RAND_MAX);   min + rand() % (max+1 - min);
 
     int arbitrary = 7;
-    int space_X = 1 + rand() % arbitrary,
-        space_Y = 1 + rand() % arbitrary,
-        space_Z = 1 + rand() % arbitrary;
+    int space_X = 2,//1 + rand() % arbitrary,
+        space_Y = 1,//1 + rand() % arbitrary,
+        space_Z = 1;//1 + rand() % arbitrary;
     int density_max = space_X * space_Y * space_Z;
     int max = fmax(space_X, space_Y); max = fmax(max, space_Z);
 
@@ -752,7 +756,7 @@ void  __attribute__((optimize("no-unroll-loops"))) main_test_graphics (void)
     /*     y    = arrows_ptr[i].y; */
     /*     z    = arrows_ptr[i].z; */
 
-    /*     write_one_arrow_vertex(buffer_vertex_size, space_X, space_Y, space_Z, */
+    /*     write_one_arrow_vertex(space_X, space_Y, space_Z, */
     /*                            load, site, x, y, z); */
     /*     buffer_colors_size = buffer_vertex_size; */
     /* } */
@@ -893,8 +897,7 @@ void  __attribute__((optimize("no-unroll-loops"))) main_test_graphics (void)
 /*         y    = arrows_ptr[i].y; */
 /*         z    = arrows_ptr[i].z; */
 
-/*         buffer_vertex_size += write_one_arrow_vertex(buffer_vertex_size, */
-/*                                         space_X, space_Y, space_Z, */
+/*         buffer_vertex_size += write_one_arrow_vertex(space_X, space_Y, space_Z, */
 /*                                         load, site, x, y, z); */
 /*         buffer_colors_size = buffer_vertex_size; */
 /*     } */