default -1 0 0 0 0 0 0 'xx' 08e8e8eh
   usage: eyecalib flag nxpts nypts pctX pctY nbox boxwid imagefile color
    defaults:       -1    5     4    95   95   5     40      -     08e8e8eh

This will calibrate eye position on the screen using a matrix of
NXPTS x NYPTS locations (e.g. 4x4).  The subject should simply look
at the box displayed in successive locations.
If you don't want to calibrate the whole screen, you can use
pctX and pctY to indicate what fraction of the screen you want
to use (default is 100% x 100%).

  FLAG options:
      0 - normal mode
	1 - scramble the order of display positions
	2 - don't preshow start location
	4 - don't erase locations
	8 - recalculate matrix from previous eyecalib file
	16 - don't display eyepos plot
	32 - save eye calibration raw data in text file
	64 - no delay between locations
     128 - save calib tables in eyecalib file
     256 - don't create eyecalib file

  If IMAGEFILE is an image file name, that image will be displayed instead of
  drawing a box.