MATLAB: Converting 3D matrix to a bigger 2D matrix efficiently

MATLABmatrix manipulation

Hello,
Let's say A is a 10x10x4 matrix. A(1,1,:) = a,b,c,d
I want to convert A to B a 20×20 matrix so that: B (1:2,1:2) = [a b;c d];
Is there an efficient way to create the B matrix without using loops?
Cheers!
Edit1: I wrote A as a 10x10x4 matrix, although in reality the matrix's size is around 20 000 x 20 000 x 4.
Edit 2: I reformulated the question:
  1. A is a huge M x N x 4 matrix
Example: 
A = zeros(M,N,4);
A(1,1,:) = [1 1 2 2]; 
A(2,1,:) = [3 3 4 4];
A(1,2,:) = [5 5 6 6];
A(2,2,:) = [7 7 8 8];
2. Convert A to a regular 2*M x 2*N matrix so that:
Example:
%Desired output:
B = 
1  1  5  5  .  .
2  2  6  6  .  .
3  3  7  7  .  .
4  4  8  8  .  .
.  .  .  .
.  .  .  .

Best Answer

[ma,na,~]=size(A);
B=permute(reshape(A,ma,na,2,2), [4,1,3,2]);
B=reshape(B,2*ma,2*na)
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