of substantially identical blocks joined together with substantially identical fastening means and extending from both sides of a center keystone thereby allowing energy efficient reliable low cost structures capable of being mass produced with minimal die or pattern expense application_number US 39156682 A description fig1 is a perspective view showing the building structure of the present invention a concrete slab 10 may be poured in a conventional manner well known in the construction industry to form a structural concrete slab which may be of any desired concrete specification depending upon the type of soil and other environmental conditions which may be encountered positioned on the concrete slab 10 are two longitudinal rows of blocks such as row 12 and row 14 these longitudinal rows comprise a plurality of modified concrete construction blocks such as block 12a 12b 12c 12d 12e 12f 12g 12h and 12i thereby forming a longitudinal row along one side of the building structure having an arcuate configuration and generally identified in fig1 with the reference numeral 15 it will be appreciated by those skilled in the art to which the present invention pertains that longitudinal row 14 also comprises a plurality of the same modified concrete construction blocks to provide a base support on which additional rows of blocks such as longitudinal rows 16 18 20 and 22 are provided keystone 100 is centrally located between rows 110 and 112 and is explained in detail in connection with fig6 it will be appreciated that after the connection and joining of the modified concrete construction blocks in accordance.