Objet Geometries have kindly offered us (in advance of even their own official press release going live) a tantalising insight concerning their new Alaris 30 Desktop 3D Printer which, despite its decidedly compact design, offers high resolution 600 x... http://amauibeach.com/blog/?p=173

Arrows, and similar marks, printed in the margins of sheets as register marks for printer and perforator. An arrow-block consists of four or more stamps, with an arrow in the margin. http://www.philatelicdatabase.com/2008...