```python
def pick_color():
global color
color = py5.random_int(255), py5.random_int(255), py5.random_int(255)
def setup():
py5.launch_repeating_thread(pick_color, name='pick_color', time_delay=1)
def draw():
py5.background(*color)
if py5.frame_count == 500:
py5.stop_thread('pick_color')
```