As long as there are well defined rules for the blocks and their positions in the matrix, direct use of the sparse() function should work well...try this
% the block
blk = [1 2 1]
% size of the block
w = size(blk,2)
h = size(blk,1)
% number of blocks
N = 5
% how much to shift blocks
vshft = 1; % vertical
hshft = 2; % horizontal
% i think this is right...
nRows = vshft*(N-1) + h
nCols = hshft*(N-1) + w
% pre-allocate
B = sparse(nRows,nCols);
% the subscripts of the original block
% these are to be shifted for indexing into the final matrix
% maybe there's a better way to do this
[jdx0,idx0] = meshgrid(1:w,1:h)
for k = 1:N
idx = idx0 + (k-1)*vshft;
jdx = jdx0 + (k-1)*hshft;
% in case you want really overlapping to add overlapping blocks
B = B + sparse(idx(:),jdx(:),blk(:),nRows,nCols);
end
full(B)
