increase as you go down and to the right on by screenthe origin is at the top-left cornerand the bottom-right corner has the coordinates ( note we'll position the ship at the bottom center of the screen to do sofirst store the screen' rect in self screen_rect wand then make the value of self rect centerx (the -coordinate of the ship' centermatch the centerx attribute of the screen' rect make the value of self rect bottom (the -coordinate of the ship' bottomequal to the value of the screen rect' bottom attribute pygame will use these rect attributes to position the ship image so it' centered horizontally and aligned with the bottom of the screen at we define the blitme(methodwhich will draw the image to the screen at the position specified by self rect drawing the ship to the screen now let' update alien_invasion py so it creates ship and calls the ship' blitme(methodalien_ invasion py --snip-from settings import settings from ship import ship def run_game()--snip-pygame display set_caption("alien invasion" make ship ship ship(screenv start the main loop for the game while true--snip-redraw the screen during each pass through the loop screen fill(ai_settings bg_colorship blitme(make the most recently drawn screen visible pygame display flip(run_game(we import ship and then make an instance of ship (named shipafter the screen has been created it must come before the main while loop so we don' make new instance of the ship on each pass through the loop we draw the ship onscreen by calling ship blitme(after filling the backgroundso the ship appears on top of the background when you run alien_invasion py nowyou should see an empty game screen with our rocket ship sitting at the bottom centeras shown in figure -