I noticed the Moire Pattern on these $1 Harvey's chips. The chips are the same, but because of the moiré patterns they appear to have different backgrounds on the inlays. From #1 to #6, the shapes in the background become more pronounced.

Moire Pattern - Moiré patterns arise when two or more patterns, such as lines, grids, or textures, are placed on top of each other, and there's a slight misalignment or difference in their spacing or orientation. The resulting moiré pattern appears as a series of wavy, rippling, or distorted lines, shapes, or colors.