The right nub is the injection point. The mold is filled from there. That is where the density and temperature, pressure, and flow differences will be most pronounced? @EvilDragon I would like to see a picture of the black case you mentioned even if/though it is ugly. It could give us an idea of how bad is bad? It may very well be impossible to fully remove this effect. Maybe it would be more pallatable to have those patterns appear in a primary color instead of black? Gradations of black tend to clash with each other. Gradations of red (or other color), for example, can be quite complimentary. I suspect that the lid with it's central fill point has an awesome sunburst pattern. Maybe this is something natural to be embraced instead of overcome? Hard to know or speculate on how a depth-less solid color would look from the blue jelly case picture where we see depth and internal textures.