The process of building a great edifice consists of working the rough rock into perfect ashlars and uniting or massing them together łon the square,˛ according to the plan of the Architect.  Each unit has to be prepared for a place and has to possess all the qualities necessary for its place.  It is the aggregation of these units that makes the structure, and to make a perfect whole, each unit must be complete and perfect as such.
According to Masonic tradition, at the Temple of Jerusalem each stone was tried, and none was passed on to the building unless it was sound and true to the plan.  When passed, besides the marks of the individual craftsman and of juxtaposition, it had also the mark of approval, without which it would not be received at the Temple.  
This latter mark was an Equilateral Triangle, held generally in the ancient east as a symbol of the Deity.  It was only put on material that had been carefully inspected and found to be of sound and according to the plan, and was therefore considered to be the Divine mark of approval.  The Equilateral Triangle, with jod or ray of light within it, was the unpronounceable name of God.  
Our Perfect Ashlar in the Northwest quadrant of the Honolulu Lodge room has both of these marks, that of the individual craftsman and the mark of approval.  You are welcome to inspect the work brothers.