| element 1 | element 2 |
|---|---|
 boiler |
 carbon dioxide |
carbon dioxide |
 fire |
carbon dioxide |
 metal |
carbon dioxide |
 pressure |
carbon dioxide |
 steel |
| element 1 | element 2 | result |
|---|---|---|
fire extinguisher |
 human |
 firefighter |
 car |
fire extinguisher |
 firetruck |
fire extinguisher |
 wagon |
firetruck |