Nearly a decade ago, Microsoft experimented with “skinput,” which projected a digital overly onto a person’s arm and turned it into an interactive interface. You could answer a call by tapping your fingertips together or press your palm to skip a song in your playlist.

With Microsoft’s Hololens 2 extended reality headset, simple taps against your skin can be used to activate features.

Google’s Soli is advancing this skinput idea: In December 2018, the Federal Communications Commission approved Google’s proposed tests of a new chip that uses radar to track micromotions. Soli is a miniature radar that understands human motion at various scales—from the tap of your finger to the broader movements of your body.

We’re already transitioning from physical to digital touchscreen buttons; soon skinput may teach consumers to live without any buttons at all.