At DDDEU23, after being invited to give a hands-on lab on modelling constraints, I was unexpectedly invited to give a talk about the book “Collaborative software design” I am writing too. This time I did it on my own, without the help of my co-authors Kenny Baas-Schwegler and Evelyn van Kelle. It is similar to the talk I did with Evenlyn at TEQNation earlier that month, with my own personal touches on the content.