XP farm house

This is a farm for experience points / XP farms. The space where the spawner must be large floats the base 8x8 blocks. First, an arbitrary block X must be legal in two corners. After water has on the blocks that the zombies / skeletons promoted to (lift). The (lift) must be high 23 blocks. And always put abwechselnt signs and water. When that is done you have to build only a walk across the room with the spawner.