Ask HN: New IoT Book structure

Dear I'd like to hear you opinion, experience and recommendation. We have task: Write a book about IoT for your students 17-18 years. Books should be used by teachers at schools, but will be also available in printed form in normal bookstore. Book also should motivate students for next study technical science. I know, goals are little bit contradictory. Teacher and students have different needs and expectations. We have following ideas about structure (areas are just illustrative): Choice A: -Electronics | |- Project A |- Project B |- Project C | - Software | |- Project A |- Project B |- Project C | - Network | |- Project A |- Project B |- Project C | - Security | |- Project A |- Project B |- Project C Choice B: Project A | |- Electronics |- Software |- Network |- Security Project B | |- Electronics |- Software |- Network |- Security Project C | |- Electronics |- Software |- Network |- Security What do you think...which structure it more suitable ? Why do you prefer certain choice? Thank you indeed for your views.