15.72.18  Consecutive_titles 

If  a title command omits the options TOP, BOTTOM, RIGHT, LEFT, X, Y, or Z
and no locations (x,y,z) are specified, then the title is placed under the
previous  one.   The  spacing  is  determined  by  the  INDEX option.  The
previous  INDEX,  ANGLE,  SIZE,  justification,  LINES,  and  SPACING  are
retained.   If  the  previous title was a 3-D title then the current title
may be placed above it, depending on the axes angle and orientation of the
view.