Small waterlogged leaf cobblestone farm

A cobblestone generator under a TNT duper. Lava and water form the cobblestone, a redstone clock runs the duper, water carries the lit TNT down onto the stone, and the blasts drop it through hoppers into chests. One TNT keeps it going and the materials are cheap, so it suits any world that needs stacks of cobblestone for building. It blows itself apart when it runs in an unloaded chunk or when the water or repeater setup is off, so stay near it and switch it off before you leave.

• Stay in the chunk while it runs and switch it off before you leave, at the same point in the clock as the video. Unloaded or stopped mid cycle, the TNT blows the farm apart. Second top comment, the creator agrees.
• Waterlog the upside down stair at 1:47 and the slab at 2:13 themselves, not the block in front, and do not sneak while placing the water. Many builders traced their blow ups to this.
• Set the repeater at 2:35 to 2 ticks, one click; two clicks blows the farm up. If the TNT lands in the lava and the cobblestone stays, raise the duper a block above the 8 at 1:11. Several builders report both.
• Build the frame from stone or tougher and keep smooth stone between the chests as in the video. Sandstone and wool get blown apart, and cobblestone between the chests stops the blasts breaking the generated stone. Several builders report it.
• On Paper or Spigot servers allow TNT duping in the server config, and turn off Redstone Experiments. Builders report the TNT never dupes or the farm fails with either one in the way.
• The scaffolding on the list is only for climbing, ladders work. Add storage, the chests fill fast. Top comment and third top comment.