to make a cobblestone generater you need to dig one space down go one right dig down two spaces go right again dig three over only one block deep put a water bucket in the first block you dug up then put a lava bucket in the block you dug last. if done right you should get an unlimited supply of cobblestone it can help if you need cobblestone at night and you don,t want to get hurt from monsters like zombies and skeletons.it might not work but if it did for you fantastic