# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 500, 350 
# set output 'param.1.png'
set dummy t,y
set key bmargin center horizontal Right noreverse enhanced autotitles box linetype -1 linewidth 1.000
set parametric
set samples 160, 160
plot t,sin(t)/t title "t,sin(t)/t or sin(x)/x"