A nine-patch block, using 4-patches!
There are so many ways to use the 4-patches you are accumulating! Here is a simple block, which in itself can be stitched as a leader or ender. The plain patches are cut 4 1/2". I chose 4 patches in neutral fabrics and one in red. Just pay attention to the direction of the dark squares in your 4-patch: mine point to the center so that a nice chain is formed.
The block, as it is shown here, measures 12 1/2", which means the finished block will be 12".