PHOENIX — As darkness fell on Steele Indian School Park on Sunday, hundreds of people gathered to watch the giant metal lotuses on the lake bloom with flames. The flowers, which appeared to float innocuously on the water all day, were rigged to shoot fire several feet on the hour after sunset in sync with songs such as Rage Against the Machine’s “Bulls on Parade” and Prince’s “Purple Rain.” Katy Strascina, executive director of Denver’s special events office, was among the crowd, taking in the mesmerizing display. “Those were so cool,” said Strascina, who stuck around to watch how the pyrotechnic installations were removed from the lake.”It gave me some excitement for what they are going to come up with in Denver.” This was part of the reason Strascina was at the inaugural Lost Lake music festival, the latest offering from festival producer Superfly.