Thanks Sury. As far as the 135 STF goes, it has great bokeh but as you would suspect, it's not very versatile. In hindsight, I think that I would rather have the 135 ZA.
For this shot I walked the length of the fence until I found a spot where I could get strong circle-bokeh that would mimic the circles and angles in the fence ornamentation.
I think that the circle bokeh in this one looks a lot like the glowing eyes of spirits or creatures lurking in the bushes.
It's caused by purple Christmas tree lights in the background.