Hey guys! I just wanted to show you guys my mob grinder so I could get some criticism on how to improve it. The main reason why I am posting this is to show you how you can easily get 30 levels in less than 3 minutes. (and maybe a few iron! ) First off in your spawner room, you will need to make the spawner area 3x5 with the spawner in the middle like so. (Where cobble is C and Spawner is S.
CCSCC
CCCCC
CCCCC

Then make a 9x4 area and put water in the corners like so.
Here comes the somewhat complicated part. You will need around 25 wooden signs to do this, maybe more. From where you're pushed into this 2 high hole, you need to put a sign like this below. Do a checkered pattern up for about 23 blocks and stop.
Then, after placing signs up 23 blocks make a 5x7x2 platform room and put water in the corners, and for the middle block make a open hole that goes down 23 blocks back to ground level. In doing this, the zombie will take up the majority of his health in fall damage so that you can kill it in a punch or two. Giving you tons of meat and experience.

As for the drop area I made a 1 block hole at the zombie's footlevel so I could hit them. Then I placed chests all around it. Like so.
So far, I've made a few chests full of rotten flesh and around 20 Iron or so using a Looting III sword.

I apologize if this tutorial was too vague or too simple. If you're confused by my tutorial there are tons on youtube. Feel free to work around this and make improvements as you go. I am open for any comments and advice and I respect your feedback. Enjoy

 

Also, I have no idea why my textures look the way they do. I hope they don't confuse you in the tutorial. I've looked for solutions and I haven't seen any. I assume its my graphics card. My computer runs this game fairly smoothly at around 50 FPS. If you guys know how I could fix it feel free to reply! Thanks!

 

Are you using the default minecraft texture pack or a downloaded/custom one?