How to use if statements and for loop to plot the following series?

I am trying to plot the following series in a subplot (6X2). The idea is to have the first column in blue, while the second in red. Besides, I would like to have a legend only in the first graph for each column that explains the meaning of the colours. I tried the following solution but it doesn't work.

VAR.tot = rand(30, 12)

x = (1:size(VAR.tot,1)).';      % Create ‘x’ To Plot Correctly
k = size(VAR.tot,2) 

t = [1,3,5,7,9,11]
d = [2,4,6,8,10,12]

for j = 1:k
    subplot(6, 2, j);
    
    if (j == t)   
    plot(VAR.tot(:,j), 'LineWidth',1,'Color', [0.25,0.3,0.8]);
    hold on
    legend('External Instrument','Location','northwest','Orientation','horizontal')
    end
  
    if (j == d)   
    plot(VAR.tot(:,j), 'LineWidth',1,'Color', [0.6,0.1,0.2]);
    hold on
    legend('Cholesky','Location','northwest','Orientation','horizontal')
    end
    
yline(0, '-')
end

What I would like to get is similar to the figure attached.

Can anyone help me sort this out?

Thanks a lot!

Answer 1

[Alan Stevens]

Try replacing

if (j == t)  

with

if (mod(j,2)==1)

and

if (j == d) 

with

if (mod(j,2)==0)

[Armando MAROZZI]

Brilliant! Thanks!