The first thing that came to my mind was a platform in a train station, but it can be anything.
I followed this tutorial [link]
and shared by
, it's really good and well explained!
Then I added a dark purple background and a tiny white frame (with GIMP).
The only thing that bothers me is that my work came out with a little noise. I have to study something to avoid noise (not completely, but a little bit at least
If you have any suggestion, you're very welcome!