Pad a vector to get matrix

I have a matrix A like above, how I can get matrix B as result of rotated matrix A in space?

Answer 1

[Mori]

A=[10 12 3 34 5]
B=A(1,1)
numel(A)

for i=2:1:numel(A)

     B=padarray(B,[1,1],A(1,i))

end

Answer 2

[Andrei Bobrov]

A = 5:-1:0;

n = numel(A);
B = zeros(2*n-1);
B(n,n) = 1;
B = A(bwdist(B,'chessboard') + 1)

or without Image Processing Toolbox

A = [10 12 3 34 5];

n = numel(A);
[ii,jj] = ndgrid(1:2*n-1);
B = A(max(abs(ii-n),abs(jj-n))+1);

or

A = [10 12 3 34 5];

n = numel(A);
p = 1:2*n-1;
z = toeplitz(p,p);
B = A((z + z(end:-1:1,:))/2);