Laying   Overlapping arcs    
No doubt this is the most commonly adopted system because it can be adapted to any surface type and dimension: this is why this system is also called “standard laying”.
archi contrastanti

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