Can an animal be chained to multiple restraints, provided they're in range? I want to chain an animal to several chains so that it's still able to bite things, but can't move at all.
Also, when you break into a cavern, is it just a sheer drop to the bottom? I don't understand how caverns work at all, can someone explain so I don't have to have Fun with my precious fort?
Ussually a cavern only lasts a few z-levels. 5 or 6 max. There are several, which may (or may not) be connected by passages. The only way to find out is dig down.
Note that it's very easy to wall off caverns if that's what you want to do. I've had 5-6 forts get down past all the caverns, to the buetifal magma sea, and have only had a single dwarf actually set foot in a cavern. That guy went splat. I've had a few cavern denizens manage to invade my fort, before I figured out how to wall them out, but none caused real fun.
Walling caverns out is fairly simple. If you dig into them from above just build a floor over the down stairway. If you break into one from the side above ground level build a wall. Breaking in AT ground level would be tricky, my basic advice is don't. If you do try to put a trench between your fort and the cavern. To do that you'll have to dig a two-tile wide trench, and remove the ramp from the cavern side. Your ramp-remover will come back up the other ramp into your fort.
BTW, just thought I'd mention that I also experience the problem with backspace not working on Macs. One of my most important burrows is named Foirges*** where * = triangle. I don't have a good explanation for you PC dorks as to why that is, because in theory a Mac "Delete" sends the same dang electronic signal as a PC "Backspace," but I do know that I can never delete anything I have typed into Dwarf Fortress.
Also some guy wanted to know exactly how much profit a trader needed. In my experience the answer is 50%. If you offer 1,500 in rock mugs the trader is quite happy to give you 1,000 worth of booze. But it's very rare for him to give you 1,001 worth of booze for 1,500 in mugs. And he'll only give you that "deal" if you previously made a proposal where he made more then 50% profit. Under no circumstances, whatsoever, regardless of skill levels, will a trader ever agree to a deal that puts him under 50% profit for the trip.