Screen interfaces teach us to think in targets, clicks, and tidy states. Installations are less obedient. People arrive from different directions, move at different speeds, and invent uses you never specified.
Unity at Sea made balance a shared input. The useful prototypes were the ones that let us observe bodies in space early, before visual polish could disguise an awkward interaction.
Prototype with the whole interaction
The result was not a larger interface. It was a different relationship between action, feedback, and the people standing nearby.