User:MentalMouse42/Sandbox/Misc Diagrams 1

Tiny Charcoal Generator
Source]

It's supposed to feed its product back into the furnace to fuel itself. However, it was an April 1 (2013) posting, so it warrants testing. At first test: Looks like it will not accumulate any charcoal in the chest until the the level-2 hopper is full.