Your quest for the perfect image that will get 100% of viewers on board with the same mathematical question may be a bit quixotic …
In [my ideal] world, I imagine spending a greater amount of time talking about the aesthetics of what makes for an interesting math problem and much less time cajoling students to ask the “right” question.
It’s unfortunate that we are so curriculum driven that we have to trick them into inventing the question we want them to come up with.
Here's the thing: nobody watches Jaws and feels cajoled into wondering the question, "Won't anybody stop that shark?!" No one watches Star Wars and feels tricked into wondering, "Will the rebels defeat the Galactic Empire?!" Those questions are irresistible, not on account of any deception on the part of the cast or crew, but because the cast and crew evoked the central conflict of their story skillfully.
This isn't to say those questions are irresistible to everybody. Some people lack the cultural prerequisites to care about Star Wars. Some people possess the prerequisites and simply don't care. Not everyone is interested in every movie, however skillfully it creates a narrative.
The point of the #anyqs challenge is to evoke a perplexing situation so skillfully that the majority of your students will wonder the same question (whatever that is) and the rest of the class won't find that question unnatural or uninteresting, even if it wasn't the first question that struck them.