Creating Matrix Using Existing Matrix

Hi, How do you create a matrix (not just a plot) that is a horizontal shear of a 2x2 identity matrix? For example, how do you create A=[1 2 ; 0 1] (identity horizontally sheared by 2)? Inputting the entries directly (A=[1 2 ; 0 1]) is not an answer that I'm looking for.

Thank you.

Answer 1

[Walter Roberson]

SheerFactor = 2;

sheermat = eye(2);
sheermat(1,2) = SheerFactor;

Answer 2

[Andrei Bobrov]

n - size matrix

full(spdiags(ones(n,1)*(0:2*n-1),1-n:n-1,n,n))

or

rot90(hankel(0:n-1,n-1:2*n-2))

Answer 3

[Julian]

Thank you all!