Parallel drainage pattern. A parallel drainage system is a pattern of rivers caused by steep slopes with some relief. Because of the steep slopes, the streams are swift and straight, with very few tributaries, and all flow in the same direction.
1 In Creative, the player can use spawn eggs to spawn most mobs. 2  When mobs are spawned this way, all normal spawning requirements, such as light level and block type, are ignored. 3  Any entity can be spawned using the /summon command.
Most farms rely on the spawning mechanisms of mobs, though other farms use mob spawners found in dungeons and abandoned mineshafts. Hostile mobs only spawn in the dark, so we have to create a large, dark room in which they can spawn.