radios, LED arrays, mini projectors, and air sensors. Click around in the Community Innovation Program forum of Finnish mobile company Jolla, and you’ll find all manner of weird and wonderful ideas for swappable back covers for its upcoming Jolla Phone. Enough to make even the wildest MagSafe accessories look a little safe and boring. It’s also the return of an old idea, which might now be bang on time—the company originally introduced “The Other Half” (TOH) modular back covers for the Jolla Phone in 2013. Like Jolla, smartphone makers are increasingly teasing modular phone concepts at trade shows like Mobile World Congress, which suggests we may be on the cusp of a mini mobile revolution. We've seen modular accessories come and go in the smartphone world over the past two decades.…