15.64.33  INTENSITY 

SET {INTENSITY|WIDTH} level [PERMANENT]
This sets the intensity level or line width  of  a  plot.   The  permanent
default is restored when a new plot is started.

level=1  to  5.  (Default:2) 5 is the brightest (widest).  If no intensity
is specified it is set to 2.
PERMANENT - Sets the current width to be the new default.