✨ This keynote talk was recorded at Lambda Days 2024. Join our Waiting List for 2025 and be part of the event next time! https://lambdadays.org ✨ Abstract I published my first paper on modelling telecoms protocols in 1989 and then implemented an interpreter for protocol languages in David Turner’s Miranda. As a consequence, I fell in love with functional programming, and I learned about the power of making equations come to life. But for me these are means to an end; it is the role of models and reasoning about them that are my focus. The types of models and techniques I have developed and used have changed over the years, and so have I. These days, my models are usually probabilistic and often developed in Milner’s Bigraphs (with extensions). Using several examples, from systems biology to mixed reality systems, I will reflect on how my research has evolved, what I have learned, and some challenges and issues we might think about in the future. Let's keep in touch! Follow us on: 💥Twitter: https://twitter.com/LambdaDays 💥LinkedIn: https://www.linkedin.com/company/lambda-days 💥Facebook: https://www.facebook.com/lambdadays 💥Mastodon: https://genserver.social/codesync