Saw this today during an inspection on a bathroom ceiling. I thought is was very cool. Its an older technique that some you may know.
When the paint is still wet, use a torch to leave carbon patterns*. Then cover with a clear coat.
Its kind of like a marble looking faux finish but it obviously isn’t marble.
The picture does not do it justice. It looks much better in real life.
*Neither Paul Hinsperger or Hinsperger Inspection Services advocates using torches or other flame producing devices in such a manner.