I need help with this plot

This code should have net B field rotating in opposite directions. I'm at a loss to make it work.

clc
clear all
close

disp('Jerry Walker''s Fantastic Engineering Adventure')
disp('EEL 3216 Problem4.4');
fprintf('\n')
format  short

% MATLAB Example of CCW Field Rotation

% M-file to calculate the net magnetic field produced 
% by a three-phase stator with currents in normal a-b-c sequence % (not flipped).

% Set up the basic conditions
bmax = 1;                % Normalize bmax to 1
freq = 60;                 % 60 Hz
w = 2*pi*freq;           % angular velocity (rad/s)

% First, generate the three component magnetic fields
t = 0:1/60000:1/60;
Baa = sin(w*t) .* (cos(0) + j*sin(0));
Bbb = sin(w*t-2*pi/3) .* (cos(2*pi/3) + j*sin(2*pi/3));
Bcc= sin(w*t+2*pi/3) .* (cos(-2*pi/3) + j*sin(-2*pi/3));

% Calculate Bnet
Bnet = Baa + Bbb + Bcc;
% Calculate a circle representing the expected maximum 
% value of Bnet
circle = 1.5 * (cos(w*t) + j*sin(w*t));

% Plot the magnitude and direction of the resulting magnetic 
% fields.  Note that Baa is black, Bbb is blue, Bcc is
% magneta, and Bnet is red. 

% Switch sign for Bbb and Bcc
Btaa = sin(w*t) .* (cos(0) + j*sin(0));
Btbb = sin(w*t+2*pi/3) .* (cos(2*pi/3) + j*sin(2*pi/3));
Btcc= sin(w*t-2*pi/3) .* (cos(-2*pi/3) + j*sin(-2*pi/3));

% Calculate Bnet
Btnet = Btaa + Btbb + Btcc;
% Calculate a circle representing the expected maximum 
% value of Bnet
circle = 1.5 * (cos(w*t) + j*sin(w*t));

% Plot the magnitude and direction of the resulting magnetic 
% fields.  Note that Baa is black, Bbb is blue, Bcc is
% magneta, and Bnet is red.

for ii = 1:length(t)  % Plot the reference circle

     subplot(2,1,1)
     plot(circle,'k');
     hold on;

     % Plot the four magnetic fields

     plot([0 real(Baa(ii))],[0 imag(Baa(ii))],'k','LineWidth',2);
     plot([0 real(Bbb(ii))],[0 imag(Bbb(ii))],'b','LineWidth',2);
     plot([0 real(Bcc(ii))],[0 imag(Bcc(ii))],'m','LineWidth',2);
     plot([0 real(Bnet(ii))],[0 imag(Bnet(ii))],'r','LineWidth',3);
     legend('Baa','Bbb','Bcc','Bnet')
     axis square;
     axis([-2 2 -2 2]);
     title('Magnetic Flux Versus Time');
     drawnow;

     % Plot the reference circle
     subplot(2,1,2)
     plot(circle,'k');

     % Plot the four magnetic fields
     plot([0 real(Btaa(ii))],[0 imag(Btaa(ii))],'k','LineWidth',2);
     plot([0 real(Btbb(ii))],[0 imag(Btbb(ii))],'b','LineWidth',2);
     plot([0 real(Btcc(ii))],[0 imag(Btcc(ii))],'m','LineWidth',2);
     plot([0 real(Btnet(ii))],[0 imag(Btnet(ii))],'r','LineWidth',3);
     legend('Btaa','Btbb','Btcc','Btnet')
     axis square;
     axis([-2 2 -2 2]);
     title('Magnetic Flux Versus Time');
     drawnow;
     hold off;
     end

Answer 1

[Image Analyst]

See this excellent link: http://blogs.mathworks.com/videos/2012/07/03/debugging-in-matlab/

[Jerry Walker]

I watched the video twice. I used Ctrl C to stop the run and when clicking the error msg I was taken to the legend function. I'm not competent to modify this function. I placed a "%" before the two legend commands and ran the program. On this occasion I was taken to the subplot function. I'm not competent to modify this function. I must admit that I realy don't understand what happens in the video.