Huh?
Are you talking sonotubes cut in half lengthwise? You’ll need to be more precise in your description.
For reference, a wall is 2-dimensional in that as a boundary, it has height and width, but no depth (apparent from within the room). If you line an entire wall with step diffusers, for example, that wall then becomes 3-dimensional as it has height, width, and now depth.
If you can show me what you are talking about or describe it better, I’ll gladly update my files!