Thought of another possibility - recipes. Person A tells Person B how to make something (possibly prompted by some pictures?), Person B follows the instructions, asks for clarification as needed, and the result is something that Person A will end up eating so they have a vested interest in some of the details of getting it right. I'm thinking about this because right now I'm making one of my personal recipes - cashew-wasabi chocolate truffles. They're vegan, gluten free, peanut free, mouth-melty, rich rather than over-sweet, and the wasabi is not hot so much as a nice flavour with a subtle feel. I've never made them from a written down recipe, I just know how to make them. But as you can imagine, if I were to try and tell someone how to do it there would be a lot of rather crucial detail I'd need to impart if they were to be edible. Not just for the wasabi, though that's rather important - chocolate itself has a complicated crystalline structure with several polymorphs and the combinations of stirring and heating that you use make a verifiable difference to the look, mouthfeel and flavour of chocolate. You want the right one, or at least one of the good ones. Not sure how good an exercise this could be made into for workshops, but recipes make for a good test of whether your instructions are specific in the right way.
Here's a possible exercise. It's about making a set of specifications that meet a pre-defined level of abstraction, not about moving between levels of abstraction.
"When I was just a wee little lad full of hope and joy
My father homeward came one night and gave to me a toy
A wonder to behold it was with many colours bright
And the moment I laid eyes on it it became my hearts delight
It went zip when it moved and bop when it stopped and whirr when it stood still
I never knew just what it was and I guess I never will."
You are a toy designer for a large educational products company. You need to come up with the latest offering in the 0-3-year-old range. Your team plans to release an new version of their Cube(TM), a six-sided shape with different bits on each side that do different things. For example, the previous Cube included a handle that when turned made a clown pop up, a button that made two other buttons appear and a squishy gel pad that changed colour when warmed by fingers. You need to specify what is on each side, what a child will need to do to that side to get a reaction, and what the reaction will be. You don't need to define the mechanism or how it will work. Firstly, you have engineers for that, who will make exactly what you want as long as you tell them exactly what you want. Secondly, it won't get your design chosen over those of the other designers (which is worth a substantial bonus). The choosing panel consists of your team's manager's manager, a couple of people from Marketing, and a small number of "typical" mums and housewives chosen for their combined decades of experience in childraising and their ability to "like" the company's updates on Facebook. Previous design runs have shown you that the panel typically tends to appreciate descriptions that are similar to the way a child of 0-3 years plays with an item - literal, clear, straight-forward, and without a lot of extra context or jargon. You also know that your manager's manager doesn't tolerate vague phrases such as "provides educational opportunities and sensory stimulation" because they don't tell him how the design is going to be more interesting than your major competitor's summer release special (or even just a stick), and that's what he wants to know.
Variation/extension 1 of this exercise is to redescribe the object to include the principle of interactivity: which is that when a child changes what they do, the Cube must also change how it responds. For instance, turning a handle faster makes a higher pitched sound and turning it slower makes the sound lower pitched. The new description needs to include how each use of the Cube can be varied and what the variable response will be.
Variation/extension 2 of this exercise is to describe a multiple-step series of operations that might include more than one face. For example, from the song: "Right on the bottom were two big buttons that looked like big black eyes / I first pushed one, and then the other / and then I lifted its lid / and when I put it down again this is what it did...".