The one thing that always stuns me is how in the hell did they (both Mojang and terrain pack creators) figure this out from math?
Like, it's perlin noise and a bunch of algorithms and it makes mountains and caves and overhangs that are all decorated and such and a river bleeding into a ravine that leads into a giant cave network.
The fantastic part about this video is just how little of actual physics you need to know to create convincing, complex waves. You can skip entire fluid dynamics and condense it to "water molecules move in circles when subjected to a wave".
Forget about Perlin noise, it is useful to getting something but it is IMO dead end if you are for realistic looking world. There isn't a way to fix it because, fundamentally, it is completely disconnected from how land features are created in real life. To get asymptotically to realism you have to start taking into account more and more of physics and passage of time and Perlin noise just completely ignores this.
To get realistic representation you need to build a little model that knows a little bit about how the features are created.
You can even go Dwarf Fortress direction and model processes that create various features of the world over time.
Like, it's perlin noise and a bunch of algorithms and it makes mountains and caves and overhangs that are all decorated and such and a river bleeding into a ravine that leads into a giant cave network.