Why is nothing drawn in PyGame at all?

i have started a new project in python using pygame and for the background i want the bottom half filled with gray and the top black. i have used rect drawing in projects before but for some reason it seems to be broken? i don’t know what i am doing wrong. the weirdest thing is that the result is different every time i run the program. sometimes there is only a black screen and sometimes a gray rectangle covers part of the screen, but never half of the screen.

How to wait some time in pygame?

While I’ve been using time.wait in my code since I began learning Python and Pygame, I’ve been wondering if there are any other ways to do it and what are the advantages and disadvantages of each approach. For example, Pygame also has a pygame.time.wait. What’s the difference between python’s wait and pygame’s wait functions? Which one is better? And are there other ways to wait some time besides using these two functions?