Wall displays, formula sheets and placemats…
If you want students to commit knowledge to long-term memory, you shouldn’t put it on the wall.

When you put knowledge on the wall, students will make use of it. Using external memory is a tremendously helpful method of reducing cognitive load. They will learn how to use the information. But they won’t learn the things on the wall.
So if you want them to learn something, help them learn it. Keep the wall for other things.