code/datums/components/plumbing/simple_components.dm 
| /datum/component/plumbing/simple_demand | has one pipe input that only takes, example is manual output pipe |
|---|---|
| /datum/component/plumbing/simple_supply | has one pipe output that only supplies. example is liquid pump and manual input pipe |
| /datum/component/plumbing/tank | input and output, like a holding tank |
| /datum/component/plumbing/aquarium | Lazily demand from any direction. Overlays won't look good, and the aquarium sprite occupies about the entire 32x32 area anyway. |
| /datum/component/plumbing/manifold | Connects different layer of ducts |