Dithering on top of pattern?

[ValisSystems]

Hi, I'm currently making a game and I've been experimenting and learning pixel art.
Recently I've been checking out dithering and one thing I had difficulty getting my head around was how I dither on top of patterns.

For instance, this is a wall with a patterned wallpaper on, and I want the bottom of the wall to be darker, hence why I dithered it.
However, when I put the wallpaper pattern on top the dithering looks quite off imo.

I'm just wondering if anybody could help give me some insight on how I should be dithering when I have patterns to include.

[Ryumaru]

You're doing it mostly correctly! This just happens to be a failure of the dithering technique- there's only so many places the pixels can go. Most pixel art pieces would avoid interactions like this for this very reason, or have a higher color count so that the dithering can be subtle and not feel like it's interfering with the pattern itself. Choosing between a darken mode, which would make the pattern fade into the shadow, and a multiply mode, which keeps it intact in the shadows, is also an artistic decision to be made.