NEW IMPROVED DESIGN:

- now produces ~540 discs per hour
- new creeper funneling system for efficiency
- increased skeleton accuracy due to block placements

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This is a modification for MushoDen's Creeper/Gunpowder Farm (https://www.youtube.com/watch?v=ueU2jFMlRn8) to turn it into a music disk/gunpowder combo farm. This base and collection system modification currently produces ~484 music disks per hour, with the exception of slightly reduced rates of gunpowder, at around 1600+ gunpowder per hour (based on several 15-minute AFK periods of testing).

The basic principle for this design is that the entrapped iron golems cause the enclosed skeletons on the opposite side of the killing chamber to aggro and fire arrows towards creepers in the middle. There is a small 1-pixel gap between the slabs and the hitbox of the campfires, causing the golems to be in line of sight to the skeletons while allowing for a minimal chance for arrows to get through. Despite this minuscule gap, arrows can penetrate to the golems (although it's very unlikely since creepers usually cover this gap while the farm is in operation). This is not really a concern for most AFK sessions, as after 1 hour, the iron golems will only be damaged a few times and can easily be repaired with a few ingots. However, for longer AFK sessions (such as an overnight), the golems might die, significantly reducing efficiency.

For most purposes, this setup may be a little unrealistic and overkill since you only really need one complete set of music disks. However, this design could be built on a server if every player wanted their own set, for instance. And of course it's easy to build and currently the best design out there so why not?