#  lucas_commands.txt
#
set term png
set output 'lucas.png'
#
#  Add titles and labels.
#
set xlabel '<--- X --->'
set ylabel '<--- Y --->'
set title 'Navier-Stokes velocity field'
unset key
#
#  Add grid lines.
#
set grid
set size ratio -1
#
#  Timestamp the plot.
#
set timestamp
plot 'lucas_data.txt' using 1:2:3:4 with vectors \
  head filled lt 2 linecolor rgb 'blue'
quit