Lecture at ICTAC School 2021: 18th International Colloquium on Theoretical Aspects of Computing, Nazarbayev University, Nur-Sultan, Kazakhstan, 1st September 2021. https://www.alandix.com/academic/talks/ICTCS-School-2021/ The second part focuses on a specific area, the formal specification and analysis of systems that have both physical and digital aspects. This will incude using physigrams, a extension of finite state networks for describing interactions with physical devices such hand-held controllers. We will also look at the ways formal analuysis contributed to the design of a internet-enabled ‘cafe open’ sign – IoT in action!