Belton House's grounds...
Fuji X-Pro2/XF23-1.4/Classic Chrome
It's actually a laser line generator across a curved surface, the material being illuminated was slightly glossy, and causes the laser line to generate the speculation reflection effect (if it was an absorbent surface like neoprene rubber, the line would look a lot more like one drawn with a pencil!!
Trying out my home made beading cutter in my home made beader/
Pete