I tried a new trick tonight. I've seen it demo'd lots of places and it's in lots of books; I'd just never tried it myself.
So, how does that happen?
Instead of pressing the center seam all one direction, you press half of it going the opposite direction--so all the center seams are now chasing each other around the block, so to speak. You then pick apart the center where all four seams come together and press it flat. See that cute little itty bitty pinwheel? How adorable is that?
Cute, but a little bit of a pain. With a pinwheel block there's all sorts of seams coming together and it takes a bit to sort out which ones want to go in which direction. You might have to pick apart a couple of stitches as well.
But boy, does it make a difference to the block. I like this little trick!