The terraformer is used to convert biomes into each other. Note that it can only convert between similar biomes - so radical changes may require multiple steps - and each stage is likely to consume a great deal of liquid and items. Give this machine a diamond and it can even mimic the world-generation of the target biome.

Select tiles to convert with the Tile Selection tool Only tiles that are the same biome as the one the machine is in can be converted

Power Input: Any horizontal side