a construction method for fabricating structures and a system of building blocks utilized in the method is presented . the blocks are hollow and may be skeletal and formed from heavy gauge strips or molded . they include at least two sub - assemblies joined by interconnecting webs with provisions for single subassemblies to square off wall edges . each skeletal subassembly includes upper and lower frames joined together by a plurality of structural columns perpendicular to the planes of the upper and lower frames . the upper and lower frames are dimensioned to form interfitting male and female receptacles that permit the blocks to be interconnected . d - lance snap fit structures are provided in the upper and lower frames so that an assembly of blocks with structural integrity may be created by snapping together courses of blocks with each course staggered relative to the adjacent course .