I too am working on Snail Tail Blocks right now. I've been taking a class that they are a part of. Here is what we are doing.
1) make your 4 patch for the center.
2) Now with the block laid down facing you, take the same color triangle as the square that is in your upper left hand corner of the 4 patch. fold the triangle in half so you can find the center, line the center up with the center of the 4 patch and sew.
3) Turn the block 180* so that you are opposite of the triangle you just put on, now again looking at the upper left corner repeat the steps In #2
4) Turn block 1/4 turn and again repeat step 2 until the round is complete.
5) Follow steps 2-4 til you have your block complete.
hope this helps. I'm enjoying making these blocks.