15.64.60  TICKS 

This determines the presence or absence of tick marks and their sizes.  To
control the default number of ticks see SET SCALE.
SET TICKS [SIZE=n] [LONG=n]
     [ALL|TOP|BOTTOM|RIGHT|LEFT|X|Y|Z] [ON|OFF]
     [INTENSITY|WIDTH=n]
     [NOCOLOR|WHITE|RED|GREEN|BLUE|YELLOW|MAGENTA|CYAN]
     [NOTEXTURE|SOLID|DOTS|DASHES|DAASHES|DOTDASH|PATTERNED|FUNNY|SPACE]
     [PERMANENT]
This  acts  on  the  current plot only if PERMANENT not specified.  If the
parameters are omitted they are reset to the original default.  To control
other individual elements of the axes use:
SET AXES, SET TICKS, SET LABELS, SET OUTLINE

(Default:ALL ON)