| element 1 | element 2 |
|---|---|
explosion |
machine |
explosion |
steam engine |
machine |
petroleum |
petroleum |
steam engine |
petroleum |
wheel |
| element 1 | element 2 | result |
|---|---|---|
cart |
combustion engine |
car |
combustion engine |
wagon |
car |
bicycle |
combustion engine |
motorcycle |