It’s interesting that all the jewelry on that page are all abstract designs, just circles or wavy lines.

Someone somewhere came up with the idea of painting a motorcycle tank using lots of layers of different coloured paint, then scraping the each layer off to reveal a shape in the colour of the next layer. When they were finished, it was a geometric shape, or a logo, or maybe even a portrait.

I tried searching for something similar, but google isn’t very helpful these days.