- There is only one direction in which products can be moved from one conveyor belt to the other.
- Products can move from a conveyor belt to a connected conveyor belt.
- A generator for a certain APC part can put such a part on its connected conveyor belt.
- Machines can only process when there is an operator at the machine.
- An operator can go from one machine to the other if the required (unfinished) part(s) is/are ready for that machine.
- An assemble machine with an operator can take two tracks, a body and a machine gun from the input conveyor belt and process them into a war APC that is put on the output conveyor belt, or can take four wheels, a body and a water cannon from the input conveyor belt and process them into a riot APC that is put on the output conveyor belt.
- A repair machine with an operator can take an (unfinished) product from the input conveyor belt, repair it, and put it on the output conveyor belt.
- A quality control machine with an operator can take an assembled piece from the input conveyor belt and in case of a successful outcome puts it on the output conveyor belt, and in case of an error puts it on the other conveyor belt for pieces that need to be reworked.
[optional] More fine grained: conveyor belts are queues.
[optional] (Unfinished) products can get "broken" arbitrarily.