Self-regenerating Wall in Minecraft

Have you ever made a fort on a server in minecraft only to for it to be destroyed in a matter of minutes? Well this wall could be the answer - it can be destroyed but then it rebuilds itself!

Step 1:

So to make your near invincible wall follow these instructions! First make a row of pistons facing upwards and connect them to a timer, then surround them with non-flammable blocks.

Step 2:

Put water on one side and lava on the other (the water has a one block "slope") to make a row of cobble-generators.

Step 3: Done!

Then activate the timer by switching the lever quickly on then off and it will start!

Step 4:

Because the cobblestone generates randomly you may want to make the timer longer. just add more repeaters!

Step 5:

If you want to make it so you can switch it on and off or want to reduce lag (or both) then you can add a sticky piston which pushes a block up and pulls it down with another lever. Ta Da!