usage: xflat2d [-h]

       Displays animations of two dimensional binary lattices.

       xflat2d expects the following formated input on standard input:

          <nx> <ny>                                 ! Dimensions of lattice
          <t>                                       ! First display time
          <val(1,1)>  <val(2,1)>  ... <val(nx,1)>   ! Lattice values
          <val(1,2)>  <val(2,2)>  ... <val(nx,2)>
                           .
                           .
                           .
          <val(1,ny)> <val(2,ny)> ... <val(nx,ny)>
          <t>                                       ! Second input time
          <val(1,1)>  <val(2,1)>  ... <val(nx,1)>   ! Lattice values
          <val(1,2)>  <val(2,2)>  ... <val(nx,2)>
                           .
                           .
                           .
          <val(1,ny)> <val(2,ny)> ... <val(nx,ny)>
                           .
                           .
                           .

       All inputs must be integers, except for the times <t> which can be 
       real-valued.  Positive lattice values <val(i,j)> are rendered as 
       white rectangles, zero or negative values are displayed as blue 
       rectangles. Lattice positions (1,1) and (nx,ny) correspond to the 
       upper left and lower right positions of the display area respectively. 

       Input is stream oriented so carriage returns are effectively ignored. 
       Thus for example, the lattice values at a given time could appear on 
       a single line, one per line, one row per line etc.