diff --git a/src/graphics/graphics.c b/src/graphics/graphics.c
index 50193d3..c97f560 100644
--- a/src/graphics/graphics.c
+++ b/src/graphics/graphics.c
@@ -684,10 +684,10 @@ 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 = 3;
-    int space_X = 2,// + rand() % arbitrary,
-        space_Y = 1,// + rand() % arbitrary,
-        space_Z = 1;// + rand() % arbitrary;
+    int arbitrary = 7;
+    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);
 
@@ -777,17 +777,17 @@ void  __attribute__((optimize("no-unroll-loops"))) main_test_graphics (void)
 
     /*   S P A C E    */
 
-    if (1) printf("buffer_lines_size before writing 12 space_ridges_lines : %d (x 2 = %d)\n", buffer_lines_size, buffer_lines_size * 2);
+    if (1) printf("buffer_lines_size before writing 12 space_ridges_lines : %d (* 2 = %d)\n", buffer_lines_size / 2, buffer_lines_size);
     write_space_ridges_lines ();
-    if (1) printf("buffer_lines_size after writing 12 space_ridges_lines : %d (x 2 = %d)\n\n", buffer_lines_size, buffer_lines_size * 2);
+    if (1) printf("buffer_lines_size after writing 12 space_ridges_lines : %d (* 2 = %d)\n\n", buffer_lines_size / 2, buffer_lines_size);
 
-    if (1) printf("buffer_lines_size before writing_space_faces_lines : %d (x 2 = %d)\n", buffer_lines_size, buffer_lines_size * 2);
-    /* write_grids_on_space_faces_lines (buffer_lines_size, space_X, space_Y, space_Z); */
-    graphics_write_line (8,  9);
-    graphics_write_line (9,  10);
-    graphics_write_line (10,  11);
-    graphics_write_line (11,  8);
-    if (1) printf("buffer_lines_size after writing_space_faces_lines : %d (x 2 = %d)\n\n", buffer_lines_size, buffer_lines_size * 2);
+    if (1) printf("buffer_lines_size before writing_space_faces_lines : %d (* 2 = %d)\n", buffer_lines_size / 2, buffer_lines_size);
+    write_grids_on_space_faces_lines (buffer_lines_size, space_X, space_Y, space_Z);
+    /* graphics_write_line (8,  9); */
+    /* graphics_write_line (9,  10); */
+    /* graphics_write_line (10,  11); */
+    /* graphics_write_line (11,  8); */
+    if (1) printf("buffer_lines_size after writing_space_faces_lines : %d (* 2 = %d)\n\n", buffer_lines_size / 2, buffer_lines_size);
 
     /*  A R R O W S  */
 
diff --git a/src/graphics/grid.c b/src/graphics/grid.c
index e23a5fa..8f218f6 100644
--- a/src/graphics/grid.c
+++ b/src/graphics/grid.c
@@ -119,6 +119,8 @@ long write_grids_on_space_faces_vertex (long x, long y, long z)
 
 long write_grids_on_space_faces_lines (long offset_vertex, long x, long y, long z)
 {
+    offset_vertex = offset_vertex / 3;
+
     for (int i = 0; i < x - 1; i ++) {
 
         /*  graphics_write_line (offset_vertex + i * 4 + 0,  offset_vertex + i * 4 + 1); */