Jean-Pierre Luminet calculated all of that back in 1979 using the IBM 7040 mainframe, an early transistor computer with punch card inputs. The machine generated isolines for his image that were “directly translatable as smooth curves using the drawing software available at the time,” he told Engadget in an email.
To create the final image though, he relied on his other passion: art. Using numerical data from the computer, he drew directly on negative image paper with black India ink, placing dots more densely where the simulation showed more light. “Next, I took the negative of my negative to get the positive, the black points becoming white and the white background becoming black.”
https://www.engadget.com/2017-04-19-black-hole-image-jean-pierre-luminet.html
Indeed. I’m just a guy who took college physics and then watched a lot of YouTube videos. But from what I have gathered, things that fall in almost completely freeze in time as they fall. So if an outside observer were able to see them (they won’t) it would look like more and more stuff getting stuck on a slowly expanding shell around the singularity.
What I find interesting is that over insane stretches of time, Hawking radiation evaporates the hole. So if you were able to survive it (you won’t), falling in would look like the universe suddenly speeding up, all stars die, and before you even reach the singularity the black hole evaporates and explodes. Leaving you in a dark, cold vacuum.
At which point the big bang possibly happens again, but that’s another story.