Laying   Circular pattern    
Another highly popular (though with an expensive laying procedure) system is the so called “circular system” – this design is obtained by laying the cubes along the line of concentric circumferences.
cerchi concentrici

For further info please refer to:

manuale porfido
manuale posa

Two books are available at Consorzio Cavatori Produttori Porfido (Italian and English)
info@porfido.net