This is similar to thing:107862 and thing:128146, except that it has shallow recesses in the underside that should fit 1 Euro cent coins when printed at the maximum size (203 mm wide) of an HP DesignJet. There is also an OpenSCAD file attached that lets you parameterize the overall size of the boomerang as well as the shape of the holes, so you can have through holes or shallow recesses, or no weights at all (not recommended). PS. For your reference: 1 cent has a diameter of 16.25 mm and is 1.67 mm thick.