% Fourier series for square wave
number = 200;
dtheta = 4*pi/number;
theta = -2*pi:dtheta:2*pi;
nharm = 20;

d = 0;
thing = d * ones(1,number+1);

for n=1:nharm
    if mod(n,2) == 1
	bn = 4/(pi*n);
    else
	bn = 0;
    end
    an = 0;
    thing = thing + an * cos(n*theta) ...
                  + bn * sin(n*theta);
    plot(theta,thing);
    axis([-2*pi 2*pi -1.5 1.5]);
    pause(1)
end