Scattered Light installation, Kings Park, part of the Perth Festival. If you recall, the lights went on at dusk and were programmed to flicker in a way that made it appear people were walking past.
(I was quite sure this was called 'Falling Light' and was perplexed why my google searches only displayed the not-at-all-related "news reader gets owned by falling light" while trying to find a link. I had to go back through my instagram to find out what I'd hashtagged it at the time. Scattered Light. Scattered. Got it.)