plot \
  "${tmp}.dat" using (tcol(1)):(column(0)) \
      title 'A' with points pt 7 ps 2 lc rgb '#7700ff', \
  "" using (tcol(2)):(column(0)) \
      title 'B' with points pt 7 ps 2 lc rgb '#0077ff', \
  "" using (tcol(1)):(column(0)):(vlength(1,2)):(0) \
      title 'C' with vectors nohead lt 1 lw 2.0 lc rgb '#227700', \
  "" using (tcol(2)+dtlabel):(column(0)):(flabel(1,2)) \
      title 'D' with labels left font 'courbd,14' lc rgb '#ff2200'