How to create big matrix that the item is small matrix

I wish to create a 252*252 matrix with 21 row and column

every item have 12*12 matrix.

So 12*12 until 21 column and row =matrix 252*252

the main diagnonal is matrix D (12*12), upper diagonal is matrix T (12*12), and the last main diagonal is matrix F.

Manually, it looks like this

%12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12

D T 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 D T 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

...

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 F

Answer 1

[Matt J]

See, How to Generate a Block Toeplitz Matrix.

Then replace the last D block with F,

Matrix(end-11:end,end-11:end)=F;