The most simple cobblestone generator possible (uses observer block) (7x3x3 : r/Minecraft
Mining and Ore Generators in Minecraft | Creating Cobblestone | InformIT
1.6.2 Fastest, cheapest and best cobblestone generator! - Redstone Creations - Redstone Discussion and Mechanisms - Minecraft: Java Edition - Minecraft Forum - Minecraft Forum
Steam Community :: Video :: Cobblestone Generator [AFK | No Redstone]
ExtendedCraft Auto Farms: Barrels, Pipes & Cobblestone Generators | Minecraft PE Mods & Addons