Here is a small sample of this worked up.

Step 1. Start with 2 closed 4mm rings

Step 2. Add 1 6mm ring.

Step 3. Add another 6mm ring, but pass through both 4mm rings and make sure it stays in front of your first ring.

Step 4. Add another 6mm ring to the other 4mm ring, make sure this one stays in back of the center (purple) ring.

Step 5. Now add a 4mm ring, passing through both the center 6mm ring and the ring behind it.

Step 6. Now add the other 4mm ring, passing through the center 6mm and the one behind it.

Now repeat from step 2 until you have the desired length. Another cool thing to do, that would look nice as a bracelet or necklace, is after each complete bubble make a spiral chain and join the bubbles together. I am working on a few projects with this stitch and will have pictures up soon.

This is what the next link looks like.