It’s interesting, when you create a monotangle, what meta patterns appear over the tile.
Here, because the basic tangle was executed across a triangular grid, circular, flower-like designs end up in the corners and sunken, shield-type shapes are offset across the tile!
I chose to add the lines to give the impression of screws in each small circle because I thought it would be more interesting and help break up the design a bit.
Zentangle drawn on Strathmore Vellum Bristol using a black, Micron pen. Shading done with graphite pencil.