Explain a Complex Concept to Different Audiences

A good explanation is not universal: it is calibrated to the listener's starting point, existing analogies, and what they already know. The same concept needs a different scaffold for a child, a smart non-expert, and a professional in an adjacent field. This builds three versions, each with the reasoning behind the approach.

I need to explain the same complex concept to three different audiences and I want a different version for each.

The concept: {CONCEPT}
Audience A: [describe, for example a ten-year-old, a complete beginner, or someone who has no background in the field]
Audience B: [describe, for example someone intelligent but from a different field, a motivated learner with some exposure]
Audience C: [describe, for example a professional or expert who knows adjacent material but not this specific concept]

For each audience: give me a clear explanation of the concept, the analogy or framing you used and why it works for this audience, and the thing you had to leave out or simplify and why.