Echoes.
I think the multiple echoes that tie up this tile are the tangle and the circular repetitions. The shapes of the Marasu and the Cogwheel echo each other. Putting the Fescu on either side of the center creates balance. Finally having the top and bottom Pinwheels echo provide a nice contrast to the more organic designs.
Zentangle drawn on Official Zentangle tile using a black, Micron pen.