I'm not an expert in programming shaders, but I have the problem that the Effect does work in the Editor without problems, but when I save the Wallpaper and try to execute it, some syntax errors prevent the layer to be visible.
If I manually edit your shader and replace the function lerp() with mix(), replace the modulo % with mod(), cast the mix- and mod-values as integers and replace the uint variables to int variables, the shader works as expected - but only as Wallpaper and not in the Editor anymore...

Any Idee, why this is happening?