What is the best way to add a series of smaller matrices to a particular point of a bigger matrix?

For example:

Starting with an empty matrix of zeros:

0 0 0 0

0 0 0 0

0 0 0 0

0 0 0 0

I would like to insert the following matrices into the larger matrix, and add elements where the matrices overlap

Small 1:

1 1

1 1

Small 2:

2 2

2 2

Small 3:

3 3

3 3

Such that the final result looks like this:

1 1 0 0

1 3 2 0

0 2 5 3

0 0 3 3

Any help would be appreciated.