Excellent article, thank you for taking the time to write this up! One cool example of conveying the hash-of-a-hash idea is the color-mixing theory found in this video: https://www.youtube.com/watch?v=-SMliFtoPn8 . It helped us understand the idea of the new hash being a mix of the previous effectively. You could include that same concept in your visualization!

A follow-up post on how forks work (soft-forks and hard-forks) would be pretty timely