I attempted to make an ideal mob farm for 1.13.2. I opened up a world with a void preset, made 4 seperate 16x16 platforms (within chunks, to make it 1.14 compatible), on Y level 3 (one of the lowest subchunks) with (of course) no other spawning areas around. I covered them in a seperate, non-spawnable platform and changed the time to night. Even at the right distance, i had absolutely zero mob spawns. What should i do?