Spielberg had recently discovered screenwriter Lawrence Kasdan and helped him sell the script for "Continental Divide" (1981). Kasdan had been working as a professional screenwriter for only one month, but Lucas agreed with Spielberg's choice after reading the "Continental Divide" script. In January 1978, Lucas, Kasdan, and Spielberg spent between three and five days at Lucas' assistant's house in Sherman Oaks, Los Angeles, working nine hours a day developing Lucas' outline. Several ideas in the finished film came from these discussions, including the boulder trap, the monkey in Cairo, Toht burning the medallion's imprint into his hand, and government agents locking the Ark away. Kasdan realized Spielberg and Lucas had several set pieces in mind, but they were looking for someone else to do the hard work of piecing them together.