My solution to crack in popcorn ceiling between foyer & dining room. Scrapped off popcorn and designed tray ceiling. First layer consisted of 12 inches of plywood around edges of both rooms, with the area between the rooms completely filled in, covering crack. Next, a strip of drywall about 7 inches wide around the edges of both rooms (filling in the area between each room, again), like a reverse wedding cake. The end result looks like two separate trays.
After arguing with hubby and contractor, that my detailed instructions would never work, I said "ok just do whatever you want". Hubby left, then contractor went to lunch. Before I left, I left contractor a note, "After rethinking this, I've decided to stick to my original plan." Viola, got just what I wanted, they ate crow. Wondering why contractors have to argue and not just do what I want.
After I painted, I made the stencils. Instead of just painting them, I used plaster.