diff --git a/src/graphics/graphics.c b/src/graphics/graphics.c
index 19a80b5..a12e03c 100644
--- a/src/graphics/graphics.c
+++ b/src/graphics/graphics.c
@@ -151,7 +151,7 @@ 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;
 
-    printf("buffer_vertex_size = %d  (%6.3f,%6.3f,%6.3f)\n", buffer_vertex_size, x, y, z);
+    if (0) printf("buffer_vertex_size = %d  (%6.3f,%6.3f,%6.3f)\n", buffer_vertex_size, x, y, z);
 
     buffer_vertex_size += 3;
 }
@@ -677,17 +677,17 @@ void  __attribute__((optimize("no-unroll-loops"))) main_test_graphics (void)
     int rand(void);
     void srand(unsigned int seed);  //    printf ("Valeur max : %d\n", RAND_MAX);   min + rand() % (max+1 - min);
 
-    int arbitrary = 30;
+    int arbitrary = 300;
     int space_X = 1 + rand() % arbitrary,
         space_Y = 1 + rand() % arbitrary,
         space_Z = 1 + rand() % arbitrary;
     int density_max = space_X * space_Y * space_Z;
     int max = fmax(space_X, space_Y); max = fmax(max, space_Z);
 
-    int show_space_design = 0, print_arrows_data = 0;
+    int show_space_design = 1, print_arrows_data = 1;
 
     int load = 0, site = 0, x = 0, y = 0, z = 0;
-    int specif_arrows_nb = 0;//rand() % density_max / 3;
+    int specif_arrows_nb = rand() % density_max / 3;
     int arrows_nb = 0;
 
     while (arrows_nb < specif_arrows_nb){
@@ -716,13 +716,13 @@ void  __attribute__((optimize("no-unroll-loops"))) main_test_graphics (void)
     offset_vertex += write_space_ridges_vertex (offset_vertex, offset_colors, offset_lines, space_X, space_Y, space_Z);
     offset_colors = offset_vertex;
 
-    printf("offset_vertex after writing_space_ridges_vertex : %d (x 3 = %d)\n\n", offset_vertex, offset_vertex * 3);
+    if (0) printf("offset_vertex after writing_space_ridges_vertex : %d (x 3 = %d)\n\n", offset_vertex, offset_vertex * 3);
 
     offset_vertex += write_grids_on_space_faces_vertex (offset_vertex, offset_colors, offset_lines, space_X, space_Y, space_Z, show_space_design);
     offset_colors = offset_vertex;
 
-    printf("offset_vertex after writing_space_faces_vertex = %2d   - 8 = %d (x 3 = %d)\n", offset_vertex, offset_vertex - 8, (offset_vertex - 8) * 3);
-    printf("(space_X - 1) * 4 + (space_Y - 1) * 4 + (space_Z - 1) * 4 = %2d (x 3 = %d)\n\n",\
+    if (0) printf("offset_vertex after writing_space_faces_vertex = %4d - 8 = %3d (x 3 = %4d)\n", offset_vertex, offset_vertex - 8, (offset_vertex - 8) * 3);
+    if (0) printf("(space_X - 1) * 4 + (space_Y - 1) * 4 + (space_Z - 1) * 4 = %3d (x 3 = %4d)\n\n",\
            (space_X - 1) * 4 + (space_Y - 1) * 4 + (space_Z - 1) * 4, ((space_X - 1) * 4 + (space_Y - 1) * 4 + (space_Z - 1)  * 4) * 3);
 
 
@@ -741,7 +741,7 @@ void  __attribute__((optimize("no-unroll-loops"))) main_test_graphics (void)
         offset_colors = offset_vertex;
     }
 
-    printf("offset_vertex after writing_arrows_vertex : %d (x 3 = %d)   (arrows_nb = %d)\n", offset_vertex, offset_vertex * 3, arrows_nb);
+    if (0) printf("offset_vertex after writing_arrows_vertex : %d (x 3 = %d)   (arrows_nb = %d)\n", offset_vertex, offset_vertex * 3, arrows_nb);
 
 
     /*---------------------------------------------------------------*/
diff --git a/src/graphics/grid.c b/src/graphics/grid.c
index 2dc8ae1..ba01a40 100644
--- a/src/graphics/grid.c
+++ b/src/graphics/grid.c
@@ -40,14 +40,14 @@ int write_space_ridges_vertex (long offset_vertex, long offset_colors, long offs
 
     graphics_write_vertex (offset_vertex + x / max, + y / max, + z / max);
 
-    graphics_write_color (0.9f, 0.2f, 0.1f);
-    graphics_write_color (0.9f, 0.2f, 0.1f);
-    graphics_write_color (0.9f, 0.2f, 0.1f);
-    graphics_write_color (0.9f, 0.2f, 0.1f);
-    graphics_write_color (0.9f, 0.2f, 0.1f);
-    graphics_write_color (0.9f, 0.2f, 0.1f);
-    graphics_write_color (0.9f, 0.2f, 0.1f);
-    graphics_write_color (0.9f, 0.2f, 0.1f);
+    graphics_write_color (0.9f, 0.7f, 0.4f);
+    graphics_write_color (0.9f, 0.7f, 0.4f);
+    graphics_write_color (0.9f, 0.7f, 0.4f);
+    graphics_write_color (0.9f, 0.7f, 0.4f);
+    graphics_write_color (0.9f, 0.7f, 0.4f);
+    graphics_write_color (0.9f, 0.7f, 0.4f);
+    graphics_write_color (0.9f, 0.7f, 0.4f);
+    graphics_write_color (0.9f, 0.7f, 0.4f);
 
     return 8;
 }
@@ -69,7 +69,7 @@ long write_grids_on_space_faces_vertex (long offset_vertex, long offset_colors,
 {
     float i, max = fmax(x, y); max = fmax(max, z);
 
-    for (i = 1; i < x; i++) {    //  (x - 2) * 4
+    for (i = 0; i < x; i++) {
 
         graphics_write_vertex ((2 * i / x - 1) * x / max, - y / max, - z / max);
         graphics_write_vertex ((2 * i / x - 1) * x / max, - y / max,   z / max);
@@ -85,7 +85,7 @@ long write_grids_on_space_faces_vertex (long offset_vertex, long offset_colors,
     offset_vertex += (x - 1) * 4;
     offset_colors += (x - 1) * 4;
 
-    for (i = 1; i < y; i++) {    //  (y - 2) * 4
+    for (i = 1; i < y; i++) {
 
         graphics_write_vertex (- x / max, (2 * i / y - 1) * y / max, - z / max);
         graphics_write_vertex (- x / max, (2 * i / y - 1) * y / max,   z / max);
@@ -101,7 +101,7 @@ long write_grids_on_space_faces_vertex (long offset_vertex, long offset_colors,
     offset_vertex += (y - 1) * 4;
     offset_colors += (y - 1) * 4;
 
-    for (i = 1; i < z; i++) {    //  (z - 2) * 4
+    for (i = 1; i < z; i++) {
 
         graphics_write_vertex (- x / max, - y / max, (2 * i / z - 1) * z / max);
         graphics_write_vertex (- x / max,   y / max, (2 * i / z - 1) * z / max);
@@ -114,7 +114,7 @@ long write_grids_on_space_faces_vertex (long offset_vertex, long offset_colors,
         graphics_write_color (0.5f, 0.5f, 0.5f);
     }
 
-    return (x + y + z - 3) * 4;
+    return (x + y + z - 3) * 3;
 }
 
 
@@ -122,7 +122,7 @@ long write_grids_on_space_faces_lines (long offset_vertex, long offset_colors, l
 {
     float i, max = fmax(x, y); max = fmax(max, z);
 
-    design = 1;
+    design = 0;
 
     for (i = 0; i < x - 1; i ++) {
 
@@ -134,7 +134,7 @@ long write_grids_on_space_faces_lines (long offset_vertex, long offset_colors, l
             graphics_write_line (offset_vertex + i * 4 + 3,  offset_vertex + i * 4 + 0);
     }
 
-    /* if (design) offset_lines += (x - 1) * 2; else offset_lines += (x - 1) * 4; */
+    if (design) offset_vertex += (x - 1) * 2; else offset_vertex += (x - 1) * 4;
 
     for (i = 0; i < y - 1; i ++) {
 
@@ -146,7 +146,7 @@ long write_grids_on_space_faces_lines (long offset_vertex, long offset_colors, l
         graphics_write_line (offset_vertex + i * 4 + 3,  offset_vertex + i * 4 + 0);
     }
 
-    /* if (design) offset_lines += (y - 1) * 2; else offset_lines += (y - 1) * 4; */
+    if (design) offset_vertex += (y - 1) * 2; else offset_vertex += (y - 1) * 4;
 
     for (i = 0; i < z - 1; i ++) {
 
@@ -161,7 +161,5 @@ long write_grids_on_space_faces_lines (long offset_vertex, long offset_colors, l
     return (x + y + z - 3) * 4;
     /* if (design)  offset_lines += 2 * (space_X + space_Y + space_Z - 3); */
     /* else        offset_lines += 4 * (space_X + space_Y + space_Z - 3); */
-
-
 }