w=c(-0.6-0.46i,0.9-0.23i,1i)

Pro32 = G.prolin(w)

Gr.postscript('29505-elica.ps',3,4.5)
latox=c(-2,2); latoy=c(-1,5);
par(bg="yellow")
Gr(latox,latoy,cornice=T)
t=seq(0,8*pi,by=0.1)
f = function (t)
  Pro32(c(cos(t),sin(t),t/6))
u=sapply(t,f)
lines(u)
lines(c(0,w[1])); lines(c(0,w[2]))
lines(c(0,w[3]))
dev.off()
---------------------------------------
# Senza sovrapposizioni.

w=c(-0.6-0.46i,0.9-0.23i,1i)

Pro32 = G.prolin(w)

Gr.postscript('29505-elica-corr.ps',
  3,4.5)
latox=c(-2,2); latoy=c(-1,5);
par(bg="yellow")
Gr(latox,latoy,cornice=T)
t=seq(0,8*pi,by=0.1)
t=c(t[t<pi-0.3],NA,t[t>pi])
t=c(t[t<3*pi-0.3],NA,t[t>3*pi])
t=c(t[t<5*pi-0.3],NA,t[t>5*pi])
f = function (t)
  Pro32(c(cos(t),sin(t),t/6))
u=sapply(t,f)
lines(u)
lines(c(0,w[1])); lines(c(0,0.55*w[2]))
lines(c(0.85*w[2],w[2]))
lines(c(0,0.5*w[3]))
lines(c(0.8*w[3],w[3]))
dev.off()