topic: Colored Petri Nets or TLA+/PlusCal

task 1: create model for the whole process associated with online shopping (Amazon, Alza.cz)
	- you should capture in particular the following steps: choosing items, payment by credit card, authorization on cell phone, checkout from store, delivery

task 2: document your solution
	- explain key overall design decisions

note: you can use either Colored Petri Nets or TLA+/PlusCal (if you are brave)

deadline: 15.2.2019