diff --git a/src/graphics/buffers.c b/src/graphics/buffers.c
index 868e917..663e6ed 100644
--- a/src/graphics/buffers.c
+++ b/src/graphics/buffers.c
@@ -426,7 +426,7 @@ static void draw_central_stars_in_neighbooring_cubes(GLuint *lines_origin,
              int space_X, int space_Y, int space_Z, int step_x, int step_y)
 {
 
-    float r = 0.0f;
+    float r = 0.0f, limit = 1.1f;
     int nb_in_neighborhood = 0;
     int s = space_X * space_Y * space_Z / 2;
 //    int z = space_Z;
@@ -438,7 +438,7 @@ static void draw_central_stars_in_neighbooring_cubes(GLuint *lines_origin,
             for (int k = 0; k < space_Z; k++){
                 if (D && (k == 0 && j == space_X - 1)) printf("                 ");
                 r = radius(i, j, k, space_X, space_Y, space_Z);
-                if (r < 1.1f){ //  2.5f
+                if (r < limit){ //  2.5f
                     if (D) printf("%6.3f (%d,%d,%d)   ", r, i, j, k);
                     draw_a_central_star(lines_origin, s + (i * step_x + j * step_y + k) * 6 + 10);
                     /* printf("buffers  : (444)  n = %d      i * step_x + j * step_y + k = %d     125 / 2 = %d\n",\
@@ -451,7 +451,8 @@ static void draw_central_stars_in_neighbooring_cubes(GLuint *lines_origin,
         }
         if (D) printf("\n                 ");
     }
-    printf("buffers  : nb_in_neighborhood = %d/%d      ", nb_in_neighborhood, s * 2 + 1);
+    printf("buffers  : neighborhood size = %d/%d   with limit = %3.1f space units      ",\
+           nb_in_neighborhood, s * 2 + 1, limit);
 }
 
 // I'm standing on Earth (any planet or star or spinning spheroid, in fact)
@@ -489,9 +490,9 @@ bool compute_space(int space_X, int space_Y, int space_Z,
     if ((space_X == space_Y) && (space_X == space_Z)) CUBE = 1;
     if (CUBE) side_size = space_X;  /* IF IT IS A CUBE,    space_x = space_y = space_z    */
     if (1) draw_central_stars_in_neighbooring_cubes(lines_origin, space_X, space_Y, space_Z, step_x, step_y);
-    if (CUBE) draw_a_central_central_star (lines_origin, s, side_size);
-    if (CUBE) draw_EW_ZA_SN_in_a_cubic_space (lines_origin, s, side_size);
-    if (CUBE) draw_3_x_4_around_6_poles (lines_origin, s, side_size);
+    if (0 && CUBE) draw_a_central_central_star (lines_origin, s, side_size);
+    if (0 && CUBE) draw_EW_ZA_SN_in_a_cubic_space (lines_origin, s, side_size);
+    if (0 && CUBE) draw_3_x_4_around_6_poles (lines_origin, s, side_size);
     printf("space (%d x %d x %d)   steps [ %d | %d | %d ]",\
            space_X, space_Y, space_Z, (space_Z + 1) * (space_Y + 1), space_Z + 1, 1);
     if (pref_test_diagonal) diagonal_test  (space_X, space_Y, space_Z, step_x, step_y, step_z, lines_origin);
diff --git a/src/graphics/graphics.c b/src/graphics/graphics.c
index c64a00e..9b808cd 100644
--- a/src/graphics/graphics.c
+++ b/src/graphics/graphics.c
@@ -563,8 +563,8 @@ static void get_model_data_and_user_preferences(){
                                         // par space_size_x, y, z et le nombre de sites
                                         // >>>  assert TODO
     pref_central_stars_nb = cubes_nb; // cubes_nb = max = space_X * space_Y * space_Z
-    pref_central_stars_nb = 0; // 1 + 6 + 24;
-    pref_central_stars_nb = 1;
+    pref_central_stars_nb = 1 + 6 + 24;
+    pref_central_stars_nb = 1 + 6;
     pref_test_diagonal = 1;
 }
 
@@ -663,7 +663,7 @@ static void compute_buffers_sizes(int space_X, int space_Y, int space_Z,
 
     buffer_lines_size += 6 * pref_central_stars_nb;  // test central stars
 
-//    buffer_lines_size -= 2;  // == TESTS LINES BUFFER SIZE ON THE DIAGONAL
+    buffer_lines_size -= 2;  // == TESTS LINES BUFFER SIZE ON THE DIAGONAL
 
     if (0) printf("allocated buffers sizes  :%4d/3 = %3d vertices, %4d/3 = %3d colors,\
  %4d/2 = %3d lines, %4d/3 = %3d plans.\n",