An 2-D symbol orientation guide with parallel and spaced right angle guidelines with chevron-like spaces provided therebetween is selectively displayed in plural selected dispositions on a monitor screen as an overlay for the display on the same monitor screen of a 2-D Data Matrix symbol. Manual rotation...http://www.google.de/patents/US7889930?utm_source=gb-gplus-sharePatent US7889930 - 2-D encoded symbol quality assessment
