Brick and aerosol can: what they have in common

1. Step 1. Brick — is material for — Hypocaust. The pillars of a hypocaust are brick.
2. Step 2. Hypocaust — evolved into — Central heating. The Roman hypocaust was an early central heating system.
3. Step 3. Central heating — has part — Valve. Valves on the radiators set how much hot water flows into a room.
4. Step 4. Valve — is part of — Aerosol can. A valve.

Open Evothings