I forgot to attach the .story file again Jonathan_Hill . Maybe it's because I wasn't entirely satisfied with the jerky rotary motion, but it still works with motion trajectories.
In a few hours, I'll make available a simplified file focusing solely on the movement of one or two tiles for the example, as the other stuff is useless for understanding the trick.
Since Monday, I've been looking for a way to do it more elegantly with JScode. After exhausting ChapGPT, I opened a discussion in the JavaScript group, which is still open, and got lots of help. I invite you to have a look. Now I just have to decide which solution I like best. I still can't code, of course, but I've learned a lot.
https://community.articulate.com/discussions/javascriptforum-board/rotating-a-shape-90%C2%B0-shouldnt-be-too-complicated-but-/1206412
Jonathan_HillA simplified file is now attached in a comment to the Review.