I was just screwing around in a flat-map (with the intention of working on another project) when I came along this village and decided to set fire to the roofings. Then I put zombies everywhere, and then ran out of villagers. Hence, whilst also practicing my redstone often, I decided to make an unnecessarily messy piston clock which would continually supply zombies and villagers. Then to spice it up since there would be hordes of zombies and one villager or something, I set up loose cannons to wittle away at the zombies and occasionally hit a villager to make it interesting. So yeah, enjoy :P