PENDENTIVE:
AN ARCHITECTURAL ELEMENT, A CONSTRUCTION FILLING.

A RECTANGULAR ROOM HAS ITS UPPER CORNERS FILLED SO AS TO FORM A BASE TO RECEIVE A DOME.

A SHAPE INVENTED BY THE ROMANS TO ENABLE THE TRANSITION FROM RECTILINEAR TO SPHERICAL, SYMBOLICALLY AND SPATIALLY MARKING THE IN-BETWEEN OF EARTH AND UNIVERSE; OF HORIZONTALITY AND VERTICALITY.