https://techcrunch.com/2021/10/21/surface-duo-2-review-getting-better/

If challenging the status quo was easy, we’d see a lot more of it. In the world of smartphones, this means daring to think outside the rectangle, a form factor that has been the default for more than a decade and a half. Slowly but surely amid stagnant smartphone sales, companies have been testing the water.

There have, in recent years, been a number of evolutionary dead ends. ZTE’s Axon M comes to mind. A valiant, if deeply flawed, attempt that was, for all intents and purposes, two smartphones stuck together. Samsung’s folding phones seemed destined for a similar fate early on.