set view equal xyz
  set ticslevel 0
  set colors classic

  set xlabel 'x'
  set ylabel 'y'
  set zlabel 'z'

  r = 130
  set xrange [-r:r]
  set yrange [-r:r]
  set zrange [-r:r]

  splot 'grid.txt' every ::313236 u 2:3:4:1 w d lc palette

  pause -1 'Press Enter to continue: '