Why doesn't this drawnow work?

I want to show the evolution of the convolution operation between two signals through time. I represent the movement in each step with a drawnow. But the last one, the convolution one, doesn't draw through time; it just moves its Y axis up and down, following what would be the line that define the convolution.

I mean: if the answer is this, for example:

the Y axis central point goes like: 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 3, 2.5, 2, 1.5, 1, 0.5 and 0. And what I finally obtain is this:

All the steps, except the last one, work perfectly (at least that's what I think). But this issue is driving me crazy!

This is my main program:

x1=[-4:0.5:4];
f1=[zeros(1,5) ones(1,7) zeros(1,5)]; 
g1=[zeros(1,5) ones(1,7) zeros(1,5)];
conv1=convolucion_e(f1,g1,x1)

This is the convolution function:

function [h2]=convolucion_e(f,g,x)
%Representación de f y g

figure(1)
subplot(2,5,1)
plot(x,real(f),'c'), legend('Real[f(x)]')
subplot(2,5,6)
plot(x,imag(f),'g'), legend('Imag[f(x)]')

figure(1)
subplot(2,5,2)
plot(x,real(g),'c'), legend('Real[g(x)]')
subplot(2,5,7)
plot(x,imag(g),'g'), legend('Imag[g(x)]')

%Abatimiento de g

g2=fliplr(g)

figure(1)
subplot(2,5,3)
plot(x,real(g2),'r'), legend('Real[g(-x'')]')
subplot(2,5,8)
plot(x,imag(g2),'b'), legend('Imag[g(-x'')]')
h=zeros(1,length(g2));
figure(1)

%Desplazamiento de g2

for a=1:length(g2)
    g3=circshift(g2,[1 a-((length(x))+1)/2]);

      %Representación

      subplot(2,5,4)
      plot(x,real(g3),'b'), legend('Real[g(x-x'')]')
      drawnow

      subplot(2,5,9)
      plot(x,imag(g3),'r'), legend('Imag[g(x-x'')]')
      drawnow

      %Multiplicación

      h1=f.*g3;

      %Integración

      h_real(a)=integ_c(x,real(h1));
      h_imag(a)=integ_c(x,imag(h1));

      h2(a)=h_real(a)+j*h_imag(a);
      subplot(2,5,5)
      plot(x,real(h2(a)),'r'), legend('Real[h(x)]')
      drawnow
      subplot(2,5,10)
      plot(x,imag(h2(a)),'b'), legend('Imag[h(x)]')
      drawnow

end

      figure(2)
      subplot(2,1,1)
      plot(x,real(h2)), legend('Parte real de la convolución')
      subplot(2,1,2)
      plot(x,imag(h2)), legend('Parte imaginaria de la convolución')

end

And finally what I get is this:

Thank you.