Oppo has used the 4th China International Industrial Design Expo (CIDDE) to showcase several new concept devices. Designed in collaboration with famed Japanese design studio Nendo, the concepts include what it calls a "slide-phone" that can be folded into different sizes and "music-link", which is described as a collection of devices centered around a pair of TWS earphones.
https://www.notebookcheck.net/Oppo-unveils-futuristic-smartphone-and-audio-device-concepts-at-the-CIDEE-Expo.509327.0.html