The thing that hangs me up with exercises like this is how to communicate how atomic the steps ought to be. The analogy misses, there. Why does the 'system' need to be told to open the jar, but not how to open the jar?
Actually when they say "Open the jar" i start beating it against the table. But yeah, most the exercise is figuring out the granularity. After they get the idea, it's quick work to give me the steps.
I've been thinking up a similar exercise, for later in the course, for concurrency. EG you can have one student get a piece of bread and apply jam, another to apply the PB, etc etc.
The best part about food-based analogies is that everybody can enjoy them and relate and they all get to snack afterward while i give a brief lecture tying the example into the coursework.
