Which parts of this blingin’ Hello Kitty calculator have been customized by the user, and which came from the factory? Was an intermediate customization step in the value chain – calculators bought wholesale by a customizer, bejewelled en masse (“bulk customization”?), and then sold  to the final user?

Button patina also gives a good clue as to the usual prices of goods at this electronics store – often less than 500(0), with the seller/bargaining customers preferring round numbers.

Also: Another calculator, another patina.