Add 2 black rings to the last 2 rings. Add another 2 black rings to the just added rings to form a 2-2-2 chain. As in step 2, the 2 rings from the 3rd link have to be folded back, one on each side. Take an open black ring and parting the rings from the 2nd link go through both of the folded back rings from the 3rd link. Add another black ring in the same place.