I thought that drawing was just a little too perfect but then realized how they might be flying such perfect lines.
All you need is a GPS-enabled tablet. Display whatever you want to “draw”, trace the outline onto your tablet screen with a grease pencil or some such, switch to map mode and scale/position the map to enclose however big you want to fly/draw, and fly that path.
The drawings would be perfectly proportioned, not made up of straight line segments, etc. The drawings would be as good as you could fly that path on your map.
This could get interesting.
Edit - found a how-to. They use ForeFlight and some other tools. Or at least the guy in the how-to video uses that.
Some cool examples there and even animations of the flights.
It’s a new art form.