This is my design of making a public server spawner warp. Many servers allow you to get spawners either buying or silk touching them and then you can place them wherever you want. If you have many spawners and its spawning more mobs than you want, it auto kills all the mobs with a timer. This is very compact and it allows you to customize it. Not all mobs will work like babies for example. The redstone can be hidden with the example of stairs shown in the world download and in the pictures. The glass blocks can be changed to any block of your choice but blocks that are being pushed by the pistons must be nontransparent. If you would like to see my public spawner you can connect to BrokenBlock's Survival server by visting their website at www.brokenblock.com or connecting to play.brokenblock.com and /warp zombie