# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 500, 350 
# set output 'stringvar.4.png'
set style data lines
set title "Constant string expressions as plot symbols" 
set xrange [ 250.000 : 500.000 ] noreverse nowriteback
beg = 2
end = 4
foo = "                                       1                                        2                                        3                                        4                                        5                                        6"
ERRNO = 0
haystack = "Sun Feb 12 19:55:42 PST 2012"
needle = ":"
S = 14
plot 'silver.dat' u 1:2:($3+$1/50.) w filledcurves above title 'Above',      '' u 1:2:($3+$1/50.) w filledcurves below title 'Below',      '' u 1:2 lt -1 lw 0.5 notitle,      '' u 1:($3+$1/50.) lt 3 lw 0.5 notitle,      '' using 1:2:( ($2>($3+$1/50.)) ? "Up" : "Dn" ) with labels         title 'plot <foo> using 1:2:( ($3>$2) ? "Up" : "Dn" ) with labels'