% Roots of the equation x^3 - 1 = 0
r1 = 1.0;
r2 = 0.5*(-1+i*sqrt(3));
r3 = 0.5*(-1-i*sqrt(3));
% Tolerance
tol = 1.0E-08;

re=linspace(-2,2,200);
im=linspace(-2,2,200);
[RE,IM]=meshgrid(re,im);
C = zeros(size(RE));
for i1=1:size(RE,1),
    for i2=1:size(IM,2),
        C(i1,i2) = randi([0,3],1);
    end
end
imagesc(re,im,C,[0,3]);
colormap('jet(4)'); colorbar;
hold on;
plot(real(r1),imag(r1),'xk','LineWidth',2,'MarkerSize',10);
plot(real(r2),imag(r2),'xk','LineWidth',2,'MarkerSize',10);
plot(real(r3),imag(r3),'xk','LineWidth',2,'MarkerSize',10);
hold off;
xlabel('real');  ylabel('imag');