Had another one lurking on my desktop:
and here’s the gnuplot code to generate it:
set terminal svg size 400,400 set output "fig-spiro11.svg" set size ratio -1 set nokey set noxtics set noytics set noborder set parametric # x(t)=(R-r)*cos(t) + p*cos((R-r)*t/r) y(t)=(R-r)*sin(t) - p*sin((R-r)*t/r) # R=100.0; r=-37.0; p=50.0 set samples 8001 # plot [t=0:320*pi] x(t),y(t)