Colorful circles generation on black background in MATLAB

MATLAB Programs:

%Code:

axis([-10 10 -10 10]);

fill([-10 -10 10 10],[-10 10 10 -10],'k');

pause(2);

hold on;

pause(0.1);

t=0:0.1:3*pi;

e=10*rand(1,length(t)).*cos(t);

f=10*rand(1,length(t)).*sin(t);

for i=1:length(e)

    x=e(i)+cos(t);

    y=f(i)+sin(t);

    plot(x,y,'linewidth',5);

    axis([-10 10 -10 10]);

    axis square;

    pause(0.1);

end