PyXPlot

Script

set dpi 100 
set wid 15
set samp 1000
set size square
set xrange [-1:1]
set yrange [-1:1]
set nokey
set x1label 'invisible:'
set x2label 'invisible:'
set y1label 'invisible:'
set y2label 'invisible:'
m = 1000.0
f1 = m
a1 = 0.4
f2 = m * 60.0/70.0
a2 = 0.6
p a1*sin(f1*x)+a2*sin(f2*x):a1*cos(f1*x)+a2*cos(f2*x) using 2:3