A modular wall block is formed with recesses or troughs in a rearward end of its top and/or bottom surface configured to receive forward portions of a rigid grid connection device. Rearward end portions of the grid connection device extend beyond the rear face of the modular wall blocks. Extended lengths...http://www.google.com.au/patents/US5522682?utm_source=gb-gplus-sharePatent US5522682 - Modular wall block system and grid connection device for use therewith
