When we talk about the design of a piece of hardware, we usually default to observations about its outward appearance–its form, its color, the materials it's made of. Often, though, that's only half the equation. For a product like the new Square Reader–a sleek update to the familiar credit card-swiping dongle that's nearly twice as thin as its predecessor–most of the design work is out of sight.
![How Apple's Lightning-Plug Guru Reinvented Square's Card Reader](https://cdn-ak-scissors.b.st-hatena.com/image/square/2530ec817b6726addb3b78430cfcc75248ef4c77/height=288;version=1;width=512/https%3A%2F%2Fmedia.wired.com%2Fphotos%2F593303d5f682204f73698223%2F191%3A100%2Fw_1280%2Cc_limit%2F131204_square_new_16.jpg)