set view equal xyz
  set ticslevel 0
  set colors classic
  set view 90,0,2.5,1

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

  set colorbox user size graph 1,0.05 origin graph 0,1
  set palette model HSV functions 4./6.*gray, 1, 1

  file = 'grid.txt'
  splot \
    file u 3:4:5:2 w d lc palette

  pause -1 'Press Enter to continue: '