the middle, or groma , the Decumanus Maximus crosses the perpendicular Cardo Maximus , the primary north-south road that was the usual main street. The Forum is normally located close to this intersection of the Decumanus Maximus and the Cardo Maximus. ......." URL:  http://en.wikipedia.org/wiki/Decumanus_Maximus     The four Masonic squares symbolizes the