How to Make a Mob Volcano in Minecraft Pocket Edition

Today were going to make a simple get awesome mob volcano. I Kidd you not, yes, a volcano of mobs!
This also works for Xbox and PC version

You will need:
1. Water
2.any building block
3. Any mob spawner

Create a tall stack of of any block about 8-15 high. Repeat 3 more times to create a tower with a hole in it

Fill you tower with anything mob you want (except chickens)

Simply add water to the inside of the top ring
Now just back up and enjoy the show

If no mobs come out check to see if:
1. Your is too high and the mobs hit the ground to hard and die
2. You placed the water in the wrong spot