Abstract: Construction blocks having a generally octagonal configuration. The octagonal shape is defined by first through eighth external side portions respectively connected end-to-end to define an octagonal shape with respective first through eighth corners; a transverse chord portion extending from said first corner to said fourth corner; a perpendicular segment portion extending perpendicularly from said transverse chord portion to said third corner defining a right angled cutout; an angled segment portion extending from said second corner to said transverse chord portion defining a triangle cutout; and a middle cutout defined by said triangle cutout, said right angle cutout and said transverse cord portion.