set terminal png transparent nocrop enhanced font arial 8 size 420,320
set output 'test18.png'
set style data linespoints
plot 'test18.tmp' using 1:2 title ',input=1,run=10,missing_test=0','test18.tmp' using 1:3 title ',input=1,run=10,missing_test=0.2','test18.tmp' using 1:4 title ',input=1,run=10,missing_test=0.4'