68 adjoining the cavities 14 16 preferably the length of end walls 6 10 is nominally 15 u215d inches while the length of side walls 4 8 is nominally 23 u215e inches the height of each of end walls 6 10 and sidewalls 4 8 is nominally seven inches each wall 4 6 8 10 may alternatively be six and three fourth inches high or eight inches high the thickness of end walls 6 19 and side walls 4 8 is nominally one and three fourth inches and each is rounded on a one half inch radius at its upper corners web 20 is nominally one and three sixteenth inches in thickness and extends between sidewalls 4 8 voids 22 24 26 are each nominally one fourth inch wide and extend approximately three and one half inches into web 20 fig4 depicts a staircase 40 constructed from blocks 2 arranged such that each next higher course of blocks 2 rests with the front sidewalls 4 thereof on the rear sidewalls 8 of the course of blocks 2 below the rear sidewalls 8 of block 2 rest on grade within blocks 2 are installed a plurality of paving blocks 76 in an array which the user finds aesthetically pleasing the paving blocks 76 are nominally four inches by eight inches in size and approximately two to three inches in height the paving blocks 76 are placed upon granular material filled in the cavities 14 and 16 of blocks 2 after the top segments 32 and 34 of webs 20 have been removed typically by blows with a hammer to.