What is this?

4 comments

1. It’s a photogrammetry marker.See what there like with a google images search.

   These onces appear to this.
   https://agisoft.freshdesk.com/support/solutions/articles/31000148855-coded-targets-and-scale-bars

2. My dad does those, it’s to track photos for restoration ir scanning and stuff like that

3. Better ask an architect. I think they are some kind of laser markers or something that has to do with structural engineering.

4. Points where aliens have visited