Ok maybe not so much a tower as a big slab, but it works nonetheless
It's larger (area wise) than misniks tower, but lower:
You can find the tower by walking the walkway from spawn fortress (the one leading towards land, not towards the water. However just looking at the tower is not that interesting. If you want to actually use it, go to my base from spawn, there are several ways to get there, both a tunnel directly from spawn fortress and via misniks tunnel system. Then follow the signs inside that points towards "Spawn Tower", and then "Collect".
Here is the collector room:
Here is what the output can look like a good day:
Unfortunately it's not that good every day, but it happens
This is what it looks like on the inside (this is the first floor, there are actually only two, so with some more work it could get a lot more efficient.
Here are some screenshots from the basement and the actual killing machines (there are four of them, and 9 trap holes leading from the main tower feeding them):
Feel free to drop by and check it out. Take whatever you like, it produces plenty of stuff and if no one is there to collect it, it just goes to waste