from Wired:

Microsoft has come up with an amazingly obvious tweak to battery tech that should save us some headaches, as well as several trillion hours of head-scratching and peering into dark holes.

Named Instaload, the invention lets you stuff the batteries into a device any which-way you fancy, eliminating the need to read dark directional diagrams. The most impressive part is the low-tech way this is handled. Each contact in the battery compartment has both positive and negative terminals. If the fat, flat end of the battery is pressing against them, it touches the outside contact. If it is the pointy positive end then it makes contact with a slightly recessed inner contact. This, combined with some simple circuitry, makes sure the current is always running the right way.

You might be surprised that this particular company produced this incredibly simple solution to a common problem. And then you read about the complex legal restrictions, and you’re not so surprised anymore.