Here is our next block set out and ready to go. The funky coloured one is the method you'd use if you're slicing the block after you've finished it.
Here the posts have been attached on all the borders and the centre square-in-a-square has been completed.
Here is the first border added.
And our block is done!
If you're making the block as two separate pieces, this is the method you'll follow.
Here I've added the posts for the borders and started working on the centre border.
And, I'm not sure what happened next. I was sure I'd taken a picture but I can't find it. So, lots happened between these pictures. I added the remaining triangles to each piece and then added the two borders.