The Selkie
One skeleton, wearing a different skin every time — floor, bed, bench, wall, or oven surround, it's the same shape underneath.
Why the name
Named for the Selkie of Scottish and Irish folklore — a seal who sheds one skin to wear another, the same being underneath every form. The exact right image for a heating principle that's identical at its core no matter what surface it's poured into.
The core shape — a fire chamber feeding hot gas through a horizontal or serpentine flue embedded in masonry mass, exhausting to a chimney — is the shared skeleton behind hypocaust floors, kang/ondol platforms, kachelofen walls, and rocket mass heater benches. Once the flue-through-mass geometry is understood, the surface it's poured into is a design choice, not a different technique.
Where This Shape Shows Up
- Floor — hypocaust (Roman/Greek).
- Sleeping platform — kang (Chinese) / ondol (Korean), see The Domovoi.
- Wall — kachelofen (Central European masonry stove).
- Bench — rocket mass heater, see The Salamander.
Real implication for future builds: don't treat a new surface application as a new technique requiring its own engineering from scratch — check whether it's just the flue-through-mass shape wearing a different skin first.