For some time now there was a bug in the game that you could duplicate rails and carpets by pushing them with pistons in a pumpking block but this bug was fixed in 1.11. Now i saw in a video a new design that can duplicate carpets now with the 1.11.1 update carpets can be used as fuel for furnaces. The furnace machine is very easy half the design is taken from Mumbo Jumbo's industrial furnace the way that the items go in the furnace is his design and i will have a link bellow to his tutorial. But how it works that's very simple a comparator check a hopper and if there is no items in it it will start the duplication machine until at least 1 carpet is still in the hopper. So with that you have unlimited fuel. Also in the hoppers are 4 items that can't be used as fuel so they will have only one slot it's the same as if it had 5 slots with carpets but it's faster to fill the hoppers the first time.

Mumbo Jumbo's Industrial Smelter : https://www.youtube.com/watch?v=7xzbx7vFqqE&t=301s