Apple's new project, codenamed Marzipan, sounds similar to the efforts Microsoft has made over the years. It's worth revisiting what Microsoft was attempting to accomplish and why it failed. Windows 8 was designed to offer a touch-friendly UI that could scale to a 32-inch monitor or run comfortably on a phone screen. It didn't offer a unified developer framework the way Apple is considering (that came later, with Windows 10 Mobile), but Metro apps were supposed to scale easily across different screen sizes. It was a great idea on paper, but it largely failed in practice. Apps designed for smal