Foldable phones are the newest and fastest-developing type of mobile computer right now. Growing out of the desire to put the largest possible amount of screen inside the user's pocket, they represent the cutting edge of technological innovation, with Samsung and Huawei offering the most notable early examples. A good foldable is one that combines the greater usability and potential of a large-screen tablet with the effortless portability of an everyday smartphone. We can expect foldables and their hinge designs to keep evolving at a breakneck pace, as hardware companies work to figure out exactly how to fold and market this new breed of portable computer.