Tesla's roof
Across
- 1. derived from the sun
- 4. costing a lot of money
- 7. what covers a roof
- 9. goal, aim
- 11. not expensive
- 12. the covering that forms the top of a building
- 13. the power from something such as electricity or oil
- 14. costing little money
Down
- 1. causing little or no damage to the environment and therefore able to continue for a long time
- 2. strength
- 3. to work with
- 5. capable of being replaced by natural ecological cycles
- 6. a person who buys goods or a service
- 8. to collect
- 10. to cause something to exist