Thanks!
Credit for that is really due to H, for posting those gorgeous, candy-striped iceburgs. After seeing those, the idea was pretty obvious.
I will clarify, though, that I'm not quite sure if DF currently models rock layers, in a visually noticeable way (as in actual rock strata). Veins seemed the more obvious choice, but only since they're very noticeable in ASCII.
By the way, in addition to materials strength, it would be great (for fossils) if there was a materials age, as well.
Possibly tied in to radioactivity (I'm thinking carbon dating, but other things have half-lives, too), and maybe rock metamorphosis, and fossil mineralization, could be modeled into that as well.
Nothing we'd ever see happening in a game, since the time-frames would be so huge, but it would be neat to have the game record that kind of info, and it would help set up prehistoric eras (which I'd really like to see someday).
Age of materials might also have much more noticeable effect on things like: wine and other alchohol, bone, iron/steel getting rusty, wood getting lighter/more stable, and eventually partially petrifying, etc.
Also, as far as cloud shapes go, maybe they could be set up with a large but finite, randomized set of basic forms (A), that could each be interpreted as "looking like ____", with a set of randomized possibilities for each dwarf, or other sentient, possibly based on personality (B)?
The basic forms could slowly shift from one to another (A1, A2, A3, A4, etc), and each dwarf that saw them could interpret them in a different way (A1 sub B1, A1 sub B2, A1 sub B3, and then A2 sub B1, B2, B3 etc.).
Hopefully, that would simulate the whole: "hey that cloud looks like a castle, no it looks like a tree, no it looks like a duck wearing a hat, yeah your right, it *does* look like a duck wearing a hat, does not, does too!...wait, now it looks like a carp wearing rollerskates" phenomena.