This chapter discusses some of the ways in which the physicality of our interactions with the world affects, drives and is exploited in the design process, and in particular how this is embodied in various physical toolkits, design applications and notations.  We first see that because user experience of devices and applications is mediated by their physicality, this then means that the physical forms used in design prototypes may subtly affect the behaviour of users.  Happily there are many tools and techniques available, so that it is possible to explore designs at different levels of physical fidelity.  These range from early stage tools such as storyboards and state-transition network representations of interaction; through off the-shelf products as video, office applications and digital toys; to specially designed physical computing kits, and electronics tools that enable bespoke working prototypes. Together, these tools can return physicality to the development process of computer-embedded products.

Keywords: Prototyping, Digital prototyping, Macquettes, Paper prototyping, Wizard of Oz, Arduino, Storyboarding, computer-embedded product design, Rig