Here are 2 different versions of Death Star coasters, one in the original state and one after it was attacked by terrorists.  I printed it with a color change at the last full layer before all of the grooves, to add contrast.  The included g-code prints both at the same time.  Each is about 82 mm diameter (3.25")  by 6.25 mm thick (0.25"). I printed one set in black and red and another in black and glow-in-the-dark green.