The present invention includes block molds and manufacturing processes as well as a composite masonry block comprising a block body having an irregular trapezoidal shape and comprising a front surface and a back surface, an upper surface and a lower surface, and first and second sidewalls. Both the first and second sidewalls have a first and second part, the sidewall first part extends from the block front surface towards the block back surface at an angle of no greater than ninety degrees in relationship to the block front surface, the sidewall second part surfaces adjoins and lies between the sidewall first parts and the block back surface. The block also has a flange extending from the block back surface past the height of the block. Also disclosed ate landscaping structures such as a retaining wall comprising a plurality of the composite masonry blocks of the present invention.