"Calling my artwork bas-relief," Mack says, "is incorrect since bas-relief technically refers to low relief sculpture. My art, in fact, has more physical depth than high relief; it incorporates various elements in full-round rising toward the viewer as in my "Illusion" image where her leg leaves the background extending into space. Technically, sculptures combining various levels of relief and full-round parts are called 'Alto Relief' sculptures. A similar technique has been used on classic Roman and Greek buildings......