Happenstance: 'chance or a chance situation, especially one producing a good result'.
I really left it too late today and I was beginning to panic. Well, taking a picture of a skip on its own is a desperate measure. Whilst doing so I became aware of someone paused behind me. We chatted briefly, I noticed her shopping bags and the idea that there might be an image here began to form. I asked her to walk through the frame and chose my moment.
Whilst I think the intention of the image is clear, what is interesting is that the idea wasn't fully formed when I took it.