That's a pattern I like tatting, it's funny that I tat it "upside down"!
I start with the scmr, then rotate and tat the ring/head with the same shuttle of the feet (that I called sh2). At this point, both shuttles are on the same side of previous arm/chain, so I turn the work from left to right and reverse all to prepare the position for tatting next chain.
But I need to rearrange threads, so: I pass under the head (its head! Not mine!) the shuttle coming from the core of the scmr, and I pass over its head the shuttle coming from the ring, that rotates.
Shuttles need to be switched to have the chains (arms) the same colour of the body.