Using the same application on different devices requires the user to perform a mental transformation in order to adapt his knowledge to a new platform. In this work we describe how this process can be employed in multi-device development. Author Keywords Platform independent user interfaces; transformation; interand intra-device consistency. ACM Classification Keywords D.2.2 Design Tools and Techniques: User Interfaces; H.5.2 User Interfaces: Ergonomics, User-centered design, Theory and methods.