/* Draw a line at the edge of the board for alignment */
-line(-hole_x, -edge_y, hole_x, -edge_y);
+real mark_y = -edge_y + mils1002mm(line_thickness) / 2;
+
+line(-hole_x, mark_y, hole_x, mark_y);
/* alignment holes */
pin_mm_clear(-hole_x, -hole_y, hole_diameter, .01, 0, "GND", "GND");