Another unique tool for Mac OS, which also allows you to import files created in Sketch and apply animations. It has a preview app for iOS—very interesting for creating and checking animations for mobile apps. Principle is a very easy-to-learn tool, as well as relatively lightweight software. You can import Sketch files and also have some animation functions. This tool fits well in projects that have lots of interaction or animations between one page and another, but that are without great features: http://principleformac.com/:
Visual representation of principle
