Clever thread title? Borg reference? Anyone? ... guess not.
Anyway, this idea came to me in another thread, but I kind of wanted to expand it out, so here goes.
Water is represented in sevenths, right? And someone already suggested making sand a 7/7 deal, so it can flow. However, thinking about it more and more, a lot of physical stuff in DF could be represented in about the same way. I know Toady is already trying to work on water-mixing, but this is a lot easier, because even if you have different layers, they don't mix. You could, hypothetically, have 2/7 sand and 2/7 water, but there's no issue with taking away one of those, and expecting it to be 50/50, since you can take just the sand or just the water.
So, what else could be measured in 7ths? Rubble, for one. After a cave in, 4/7 or greater would be completely blocked off (although only 7/7 would prevent water or such from flowing through), whereas 1/7 or 3/7 would only slow the dwarves down, until it was cleared.
This could also be used during mining, to deal with the whole "somehow the stone has been atomized" issue. Mining would require a few diggers and a few haulers, or heck... mining carts, to mass-transport large quantities at once? Who doesn't love mine carts.
Could also be a part of ore or gem gathering. Gems could be 1/7 actual gems, 6/7 the surrounding rock. Ores or even rock types could also be mixed.
For that matter, rather than the weird twilight world of floors now, where the sort of exist as nothing or something a bit at random, floors could be just a 1/7 layer to walk over, which would also make that nice gold floor off in the middle of nowhere movable. Or better yet, "regular" floors could just be the layer below, but if you wanted a "walkway" floor hanging over nothing, that'd take a 1/7 of something.
And, of course, sand makes a good 7/7, credit to the first guy who suggested it. But that means that soil is also a 7/7, which means that getting soil underground could be a much easier matter of just dragging a single unit of soil over, like the "bucket brigade" watering.
For that matter, different things could require different amounts of soil. Maybe fungus needs only 1/7 soil, but a root-plant needs 3/7 soil, and trees need a full 7/7 soil, IE the layer under them has to be soil.
Stockpiles could also be in 7ths, although possibly different items would take up more or less space. A few rings make up 1/7, but a bed takes up 4/7.
Workshop clutter, too. Now, if you leave a pile of stuff around, the workshop gets "cluttered" semi-arbitrarily. But if those things take up actual space, the workshop might be cluttered by being physically covered in stuff you didn't haul away.
Now, as far as CPU power goes, aside from maybe the sand, there'd be no actual calculations beside the existing "no longer connected to the ground" one. It wouldn't lag like water because it wouldn't move around, it'd just use an existing system to make it easier to implement.