Here is our next block set out and ready to go.
Here is the block with the centre square-in-a-square assembled. Plus, I added the posts to the dark triangles and started assembling the triangles in the outer corners.
Now I've completed the outer corners of the block and the centre square. For the centre square, I used the square-in-a-square method and then trimmed it down to size. This way I was able to use the simple building blocks without fussing with centering things or any funny cutting. It does waste a little fabric though.