Elevator simulation is used often as a case study for petri nets. There is quite a bit of PN material using elevators.<p>Eg <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=59jW9dngt_c" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=59jW9dngt_c</a><p>PNs are a great way of modelling the concurrent state handling required for something like this.