Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_24 (surface VARCHAR, partner VARCHAR)
### Question:
What surface was played on when Piet Norval was a partner?
### Answer:
SELECT surface FROM table_name_24 WHERE partner = "piet norval"