With my newly-acquired mastery of Block Update Detectors, I have created this little thing. It never creates more than three cobblestone blocks, but whenever you break one of them, it automatically creates another cobblestone block to fill the gap and pushes it to where it needs to be. Due to the way pistons work, it is possible, but unlikely, to get one of the pistons to un-stick from the wool. There is a reset button to fix this.
Picture Added April 22, 2012, 11:12:30 AM (-07:00)
Added by A'bom