This is the Flying Geese pinwheel Block and the tutorial can be found over at Sew Happy Geek (here).
And this block, which I don't know the name of, has become one of my favourites overall. The tutorial can be found as part of the In Color Order HST Block of the Month QAL here.
Although it was bitterly cold today, the sun was at least shining so I popped outside for a photo for a change :)
I've been squaring up my blocks and have found that a couple are coming up short of the required 12.5" - humph!
Linking up with Fabric Tuesday at Quilt Story