Basically just a Snail's Trail block. I have them in one of my original designs. They look intimidating but they're actually pretty easy. You start off with a four patch in the middle and then add a triangle to each side to make a bigger block and add a triangle to each side to get an even bigger block. Its simple. Just watch and make sure you're putting on the right colored triangle. Have the image of the block handy for reference. But once you've done a couple blocks you'll get the set up.