[antsar]

Perhaps the magnetic tape recorder and cell phone weren't the best examples of "unintended uses", but using chest x-rays as phonograph records is a clever hack.

Smartphones are intended a a personal device running apps controlled by a human user (sure, a "platform"). They're not intended to be a sensor pack / CPU for self-driving cars.

3D printers are intended for printing plastic stuff (sure, arbitrary plastic stuff). But maybe they can be co-opted for squirting molten plastic at your enemies.

Quadcopters are intended for doing arbitrary stuff while hovering. But you could re-purpose one as an oscillating fan.

[swiley]

I've experimented with my 3d printer by attaching a wire connected to a capacitor bank to the tool head. I can cut (with low accuracy) metal foil that's connected to the other end of the capacitor bank this way, I never did more experiments with it.