# set terminal canvas  rounded size 600,400 enhanced fsize 10 lw 1.6 fontscale 1 name "discrete_3" jsdir "."
# set output 'discrete.3.js'
set contour base
set cntrparam levels incremental -20,5,10
set style data lines
set title "9 incremental contours starting at -20, stepping by 5" 
splot x*y