n number of 2x2 matricies to diagonal matrix

I have a 2x2 matrix that I need put into the diagonal of a matrix n times. In other words, on each diagonal, a new 2x2 matrix prints. For cells with two k values, they should be added together.

For example:

n = 3:

k -k 0 0

-k k+k -k 0

0 -k k+k -k

0 0 -k k

What I have:

n = input('Input the number of elements:');

k = ((E * avg_area)/L)*[+1 -1; -1 +1];

for n;

k_global = diag(k);

end

Answer 1

[David Hill]

n = input('Input the number of elements:');
k = ((E * avg_area)/L); 
k_global=diag([k,repmat(k+k,1,n-1),k])+diag(repmat(-k,1,n),-1)+diag(repmat(-k,1,n),1);

[k]

Thank you so much!