SWIFT：如何随机选择5个障碍中的1个并对其进行操作，并每秒重复此过程？

I am trying to create a game where there are five different obstacles, one of which is selected at random every second, and moves from the top of the screen to the bottom of the screen. This should create an obstacle field for the player to navigate. I am able to have the first obstacle move down the screen, but instead of another coming down the screen a second later, I keep getting Thread 1: signal SIGABRT errors, despite trying to fix the problem.I am trying to create a game where there are fi