Sandy Caves

I tried to come up with a cave biome that is as simple, unambitious, & easy to implement as possible, while still being interesting enough gameplay-wise that it's something worth adding. And what I came up with is the Sandy Caves Biome.

This biome sometimes generates under the desert biome, and has lots of sandstone & sand on it's walls & ceilings going all the way down to y=30 or 20 or something.

What makes this unique as a biome is the sand floors & ceilings providing a unique challenge for it, since a player would need to be extra mindful of where they mine & where they're stepping as, sometimes, the floor or ceiling or both could collapse at any moment. Potentially dumping 20+ blocks worth of sand onto the player, or dropping the player potentially 20+ blocks deep.

This shouldn't be too difficult to implement since it's basically already in the game; caves near the surface in desert biomes sometimes spawn with sandstone for walls & sometimes sand for ceilings. All we have to do is extend the effect lower down to lower y levels & increase the likelihood that the floors & ceilings are made out of sand, and my suggestion is done.