OnePlus’ one-trick concept phone is exactly what CES is all about

Last night at the CES trade show in Las Vegas, Chinese phone brand OnePlus finally showed off what it’s been working on for 18 months: A phone with custom-manufactured glass that can hide its rear cameras by turning opaque when they’re not in use. No, it’s the not the biggest deal in personal technology right now, and it does seem like OnePlus went to a whole lot of trouble to showcase a single feature (okay, two features — the glass opacity control allows it to fill in