How can I make this simple image on matlab?

I need to be able to recreate this image attached on matlab. Is this possible? Thank you

Answer 1

[KSSV]

m = 50 ; 
A = zeros(m) ; 
N = 10 ; 
for i = N:N:m
  n = m-i ; 
  t = ones(1,n) ; 
  A = A+diag(t,-i) ; 
end

for i = N:N:m
  n = m-i ; 
  t = ones(1,n) ; 
  A = A+diag(t,i) ; 
end
A = A+diag(ones(1,m)) ; 
A = A+fliplr(A) ; 
pcolor(A)
shading interp 

[Love Matlab]

Thank you! Is it possible to make all the diagonal lines solid? This is the image I get with your code