th=0:0.001:2*pi;
z=zeros(3,length(th));
for i=1:length(th)
    t=th(i);
    A = [ cos(t)    sin(t)*(1-cos(t))      sin(2*t) 
            -1             0            sin(t)+(cos(t)-1)/3
       -2*sin(2*t)       sin(t)            -cos(t)              ] ;
    z(:,i)=eig(A);
end
hold on
plot3(th,real(z(1,:)),imag(z(1,:)),'b-')
plot3(th,real(z(2,:)),imag(z(2,:)),'r-')
plot3(th,real(z(3,:)),imag(z(3,:)),'g-')