8. TIC MARKS:


   This option allows you to place tick marks on both the X and Y
axes.  You may select from 0 to 25 marks.  If a number less than 0
is entered, no tick marks will be generated, and if a number greater
than 25 was entered, 25 tick marks will be displayed.  The default
is a plot without tick marks.

   The user is also given the option of selecting a grid to be drawn
over the display window instead of having discrete tic marks.  The 
lines of the grid are determined by the position of the tic marks.  
