diff --git a/src/graphics/grid.c b/src/graphics/grid.c
index 2e7ed0f..ca17bb4 100644
--- a/src/graphics/grid.c
+++ b/src/graphics/grid.c
@@ -52,7 +52,7 @@ void write_space_ridges (long x, long y, long z)
 
 void write_marks_along_space_ridges (long x, long y, long z)
 {
-    float i, j, k, vx, vy, vz, max = fmax(x, y);
+    float i, j, k, vx, vy, vz, max = fmax(x, y);    int kin = 0;
                                max = fmax(max, z);
 
     for (i = 0; i <= x; i++)
@@ -64,48 +64,68 @@ void write_marks_along_space_ridges (long x, long y, long z)
                 vz = (2 * k / z - 1) * z / max;
 
                 if (
-                    (i == 0 && j == 0) || (i == 0 && j == y) || (i == x && j == 0) || (i == x && j == y)
-                ||  (i == 0 && k == 0) || (i == 0 && k == z) || (i == x && k == 0) || (i == x && k == z)
-                ||  (j == 0 && k == 0) || (j == 0 && k == z) || (j == y && k == 0) || (j == y && k == z)
-                )
-                graphics_write_vertex (vx, vy, vz);
+                    (i == 0 && j == 0 && k > 0 && k < z)
+                ||  (i == 0 && j == y && k > 0 && k < z)
+                ||  (i == x && j == 0 && k > 0 && k < z)
+                ||  (i == x && j == y && k > 0 && k < z)
+                ||  (i == 0 && k == 0 && j > 0 && j < y)
+                ||  (i == 0 && k == z && j > 0 && j < y)
+                ||  (i == x && k == 0 && j > 0 && j < y)
+                ||  (i == x && k == z && j > 0 && j < y)
+                ||  (j == 0 && k == 0 && i > 0 && i < x)
+                ||  (j == 0 && k == z && i > 0 && i < x)
+                ||  (j == y && k == 0 && i > 0 && i < x)
+                ||  (j == y && k == z && i > 0 && i < x)
+                )   {
+                        kin ++;
+                         graphics_write_vertex (vx, vy, vz);
+                    }
             };
+printf("n = %d\n", kin);
+
+    int vertex_offset = 8;
+
+    graphics_write_line (vertex_offset + 0,  vertex_offset + 6); //
+    graphics_write_line (vertex_offset + 1,  vertex_offset + 7); //
+
+    graphics_write_line (vertex_offset + 2,  vertex_offset + 3); //
+    graphics_write_line (vertex_offset + 4,  vertex_offset + 5); //
+
+    graphics_write_line (vertex_offset + 8,  vertex_offset + 9); //
+    graphics_write_line (vertex_offset + 12,  vertex_offset + 13); //
+
+    graphics_write_line (vertex_offset + 10,  vertex_offset + 11); //
+    graphics_write_line (vertex_offset + 14,  vertex_offset + 15); //
+
+    graphics_write_line (vertex_offset + 18,  vertex_offset + 19); //
+    graphics_write_line (vertex_offset + 20,  vertex_offset + 21); //
+
+    graphics_write_line (vertex_offset + 16,  vertex_offset + 22); //
+    graphics_write_line (vertex_offset + 17,  vertex_offset + 23); //
+
+    /* graphics_write_line (buffer_lines_offset + 20,  buffer_lines_offset + 21); */
+    /* graphics_write_line (buffer_lines_offset + 22,  buffer_lines_offset + 23); */
+
+    /* graphics_write_line (buffer_lines_offset + 1,  buffer_lines_offset + 21); */
+    /* graphics_write_line (buffer_lines_offset + 2,  buffer_lines_offset + 22); */
+
+    /* graphics_write_line (buffer_lines_offset + 0,  buffer_lines_offset + 20); */
+    /* graphics_write_line (buffer_lines_offset + 3,  buffer_lines_offset + 23); */
+
+    /* graphics_write_line (buffer_lines_offset + 17,  buffer_lines_offset + 25); */
+    /* graphics_write_line (buffer_lines_offset + 18,  buffer_lines_offset + 26); */
+
+    /* graphics_write_line (buffer_lines_offset + 5,  buffer_lines_offset + 25); */
+    /* graphics_write_line (buffer_lines_offset + 6,  buffer_lines_offset + 26); */
 
 
-    int buffer_lines_offset = 12;
+    /* graphics_write_line (buffer_lines_offset + 5,  buffer_lines_offset + 25); */
+    /* graphics_write_line (buffer_lines_offset + 6,  buffer_lines_offset + 26); */
 
-    graphics_write_line (buffer_lines_offset + 5,  buffer_lines_offset + 25);
-    graphics_write_line (buffer_lines_offset + 6,  buffer_lines_offset + 26);
+    /* graphics_write_line (buffer_lines_offset + 0,  buffer_lines_offset + 1); */
+    /* graphics_write_line (buffer_lines_offset + 1,  buffer_lines_offset + 2); */
 
-    graphics_write_line (buffer_lines_offset + 1,  buffer_lines_offset + 0);
-    graphics_write_line (buffer_lines_offset + 2,  buffer_lines_offset + 3);
 
-    graphics_write_line (buffer_lines_offset + 8,  buffer_lines_offset + 9);
-    graphics_write_line (buffer_lines_offset + 10,  buffer_lines_offset + 11);
-
-    graphics_write_line (buffer_lines_offset + 9,  buffer_lines_offset + 11);
-    graphics_write_line (buffer_lines_offset + 8,  buffer_lines_offset + 10);
-
-    graphics_write_line (buffer_lines_offset + 12,  buffer_lines_offset + 13);
-    graphics_write_line (buffer_lines_offset + 14,  buffer_lines_offset + 15);
-
-    graphics_write_line (buffer_lines_offset + 12,  buffer_lines_offset + 14);
-    graphics_write_line (buffer_lines_offset + 13,  buffer_lines_offset + 15);
-
-    graphics_write_line (buffer_lines_offset + 20,  buffer_lines_offset + 21);
-    graphics_write_line (buffer_lines_offset + 22,  buffer_lines_offset + 23);
-
-    graphics_write_line (buffer_lines_offset + 1,  buffer_lines_offset + 21);
-    graphics_write_line (buffer_lines_offset + 2,  buffer_lines_offset + 22);
-
-    graphics_write_line (buffer_lines_offset + 0,  buffer_lines_offset + 20);
-    graphics_write_line (buffer_lines_offset + 3,  buffer_lines_offset + 23);
-
-    graphics_write_line (buffer_lines_offset + 17,  buffer_lines_offset + 25);
-    graphics_write_line (buffer_lines_offset + 18,  buffer_lines_offset + 26);
-
-    graphics_write_line (buffer_lines_offset + 5,  buffer_lines_offset + 25);
-    graphics_write_line (buffer_lines_offset + 6,  buffer_lines_offset + 26);
 }