MATLAB: Please help me how to describe a matrix in terms of smaller matrices.

Question

For example,

Let A=[1 2 3; 4 5 6; 7 8 9 ] and

A11 = [ 1 2; 4 5] , A12 = [ 2 3 ; 5 6] , A21 = [ 4 5 ; 7 8], A22 = [ 5 6; 8 9]. So I wanted to express A in terms of A11, A12, A21, and A22.

Answer 1

Is it sure they overlap by one line/column? Then it's just

 A=[A11 A12(:,2:end);A21(2:end,:) A22(2:end,2:end)];