Polygonal retaining wall of the Temple of Apollo at Delphi, Greece, built in the 6th century BC. Polygonal masonry, also known as 'Lesbian Masonry', is a technique of stone construction of the ancient Mediterranean world. True polygonal masonry may be defined as a technique wherein the visible surfaces of the stones are dressed with straight sides or joints, giving the block the appearance of a polygon. This technique is found throughout the Mediterranean and sometimes corresponds to the less technical category of Cyclopean masonry. An important feature of polygonal masonry is it's resistance to seismic shocks making structures built by this method virtually earthquake proof.