The decs spiral because they're done at the same place on every other row. If you have say 80 sts, you would k8, k2tog across the first dec round. Then knit a round with no decs, and on the next one k7, k2tog. Plain round, and dec round of k6, k2tog. Repeat doing one less knit st between decs. When you get to about 32 sts, do the decs every round.