Minecraft wiki entry for Before_1.18, associated text: At this stage of biome generation, the final climate zones were applied as follows. Areas of dry landmasses were assigned to be a normal biome if it bordered a cold or frozen landmass. Areas of snowy landmasses were assigned to the cold temperature category if it bordered a normal or dry temperature zone. 1 out of every 13 landmasses was then marked as "Special", which would be used to place some of the rarer biomes in later stages of biome generation. This map was then scaled twice, until a scale of 1 to 256. An additional layer was applied to create a more jagged coastline, creating areas of large islands and lakes around the coastline. 1 out of 100 areas of oceans were assigned as mushroom biomes and areas of ocean far from the coast converted into deep ocean.