Abstract: A hollow module useful for a retaining wall structure or the like defined by an upstanding surrounding wall formation presenting front, rear and opposed side faces and having generally planar upper and lower surfaces and a substantially constant wall thickness throughout the extent of any given face, the lower planar surface in the regions of the opposed side faces presenting at least a pair of opposed depending lug formations projecting therebelow of dimensions such that when measured in the front to rear direction the extent of same are always less than the front to rear extent of the opposed side faces so as to define with the lower planar surface recess formations for selective registration over the upper planar surfaces of other like or compatible modules whereby such modules are selectively interlockingly interengaged; and wherein suitable slabs are provided with depending lug formations projecting therebelow for disposition upon upper planar surfaces of such modules with the lug formations projecting t

Abstract: An interlocking block and a retaining wall system derived from such blocks wherein the blocks when arranged to extend in horizontal courses in end to end relation and one upon the other in interlocking overlapping wall defining relation automatically uniformly incline to the vertical, such interlocking block having an axis terminating in spaced apart end walls and bounded by generally flat top and bottom walls arranged in parallel relation to each other and by front and rear facings extending from end wall to end wall and so spaced apart as to provide a substantially uniform cross-section throughout the axial extent of same, the block having an axially extending projection upstanding from the top wall and the bottom wall having an axially extending recess formation of a configuration and extent to match the projection, the projection being spaced inwardly from the front facing to present an uninterrupted flat top wall portion therebetween and rearwardly in relation to the axis a selected extent exceeding that