Apple has applied for a patent that shows how the backlight on its devices could be used as a safety light for runners or a party accessory that could be synchronized to music. The patent application, filed in May and published today, is titled “Handheld devices as visual indicators.” According to the filing, the light transmitted can be configured with playlists on a device, and the music “varies the light level transmitted by the display in accordance with the song being played.” While that’s fun (and detrimental to your battery), another function appears a bit more practical.

The application also notes that the backlight could be configured to act like a light beacon for night runners. This can be used to alert other pedestrians or cars of the runner’s presence. The light in its beacon mode could blink, fade in and out, pulsate, or strobe. Apple envisions this use case with an illustration of a runner with the device strapped to their arm.

While these are pretty nifty features, as with most patents Apple applies for, the idea may never turn out to be an actual Apple feature (nor will the patent actually get approved.) If you want a similar effect now, there are already a host of third-party apps on the App Store that let you turn your phone into a music strobe and those that produce a beacon light for pedestrians and runners.

Sourtce: theverge