% Draw a line in a 3D space
title('Demo of plot3');
z = linspace(-4*pi,4*pi,100);

hold on
h1=plot3(cos(z),sin(z),z,'r');
h2=plot3(-cos(z),-sin(z),z,'b');
set([h1 h2],'LineWidth',3);
axis([-4 4 -4 4 -13 13]);
hold off

set(gca,'CameraPosition',[0 40 3]);
