I'm autistic and I think a bit differently. I have superior memory and visual thinking, but I have a problem with converting real thing to abstract. I'd like to model reality processes with Petri nets. But... when I think of cooking meal or using a coffee vendor machine, I see in my head vegetables, kitchen utensils, cooking books and coffee machines I have seen in my entire life, but no graphs.

I am able to draw for example binary counters, because their graphs look like real things. But I can't see Greek salad as a graph. I need some help. When I see the examples, I should learn it all very quickly, but now I have nothing to start and nobody to ask.

  • $\begingroup$ Petri nets serve well for modelling processes, so (naturally) modelling static objects is going to be weird. Find processes you associate with the given object and visualize these; in a sense, you'd "specify" an object by its interaction interface, not its properties. $\endgroup$
    – Raphael
    May 22, 2015 at 13:10

1 Answer 1


I'm not sure how to approach your particular problem, but here is an attempt.

Consider the recipe you are using as a collection of steps, some of which depend on others; for a salad you might have "make dressing", "shred lettuce", "slice cucumber" etc. The dependencies are given through resources, which here are ingredients, possibly in some processed state, like oil, vinegar, cucumber, sliced cucumber, etc.

To model this process as a Petri net, you use

  • places to represent the various resources, i.e. you have a "vinegar" place, a "shredded lettuce" place, etc,
  • tokens on those places to represent the amount of each resource you have; initially this would be something like one token on each unprocessed ingredient,
  • transitions to model actual steps in the recipe; for example you could have a "make vinaigrette" transition consuming a token from the "oil" and "vinegar" places and producing a token in the "dressing" place.

The amount of detail here depends on what you want to do with the model; you might for example want to keep track of equipment in addition to ingredients (with the "make vinaigrette" transition additionally consuming a clean whisk and producing a used whisk), etc.

Is this the kind of example you had in mind?

  • $\begingroup$ Thank you a lot. I had a visual example in mind, because I learn with pictures. $\endgroup$
    – złyVlojk
    May 25, 2015 at 11:32

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