In this piece they've used this continuous line-drawing to tell a story. From what I can see, the animator has used a stroke mask to reveal the images, but it was the way the line drawing morphed into other shapes that I was trying to figure out. Is this something can be easily achieved in After Effects, or does it require more traditional and more (time-consuming!) animation techniques? Thanks a lot for your time guys!
Not sure there is an 'easy/straightforward' way to create this style in After Effects.
You could get something similar, but not as complex using the stroke effect and masks, but there was a LOT of work behind the scenes in those.
Either someone hand drawing them, or hand animating the masks and stroke to make it all work.
It's very possible that this is sort of an offshoot of rotoscoping, in that the video or visual reference was put together in an extended comp, and then the comp was used as a guideline for the animated paint. This would make it much easier to achieve than say, from a storyboard. Still a tedious and involved job. And a very creative approach to an uncomfortable topic.