Early Summer
Progress is going well

Most of the traps and hallways have been dug out.

The prisoner arena didn’t exactly look the way I imagined it, but I guess it’ll have to do.
(and yes, the additional doors between the legs of the goblin corpse shaped Prisoner arena are there for “extra protection”)
It's even multicolored
I’ve revamped most of the economy, laying off more than half of the engravers and crafters while tripling the number of miners and mechanics.
I”ve also drafted a few extra recruits into the military to bolster our forces, but preferring to do the dirtier stuff with mechanisms rather than beard, I’ve mostly just left the squads of candy clad warriors to manage themselves.
The dwarves are busy, work is being done efficiently, no one is having any temper problems and everything is just fine…

Oh noes! a snatcher!
Catching some of the nearby dwarves off guard, he strikes down a peasant and heavily injures one of the recruit hammerdwarves before running away.
And with snatchers there will inevitably be…

Oh noes! An ambush!
did they change the symbol for goblins?
I was just about to dispatch the military when one of the dwarves mentioned to me that a specific creation used to release magma upon the creatures of the surface was built by a previous overseer just for this situation.
A brief overview of the construction had impressed me, but judging from the designs, I saw grave inefficiencies. Though the device held the potential to destroy armies, its situated position and unnecessarily long release paths meant it would be slow and clumsy with its deployment. I also could not, for the love of all that is dwarvenly, understand why the designer of this magma machine decided that it would be perfectly fine to allow a goat pass above the machine’s blast zone where any would be assaulters could just simply waltz by harm free straight into our fort.

Theoretical outcome of releasing the magma
And it would also endanger the lives of any dwarf who happened to wander outside as well.
So should I send the army or pull the lever?
who was the player who built the magma release device again?
And how do I make the goblins go through the spiral hall of cage traps? When I gave the ambush a test run, all of the Goblins just simply path through a little tunnel near the entrance into the fort