# 9.6: The main() Function

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def main():
global FPSCLOCK, DISPLAYSURF, BASICFONT, L_SQUIR_IMG, R_SQUIR_IMG, GRASSIMAGES

pygame.init()
FPSCLOCK = pygame.time.Clock()

The first several lines of the main() function are the same setup code that we’ve seen in our previous game programs. The pygame.display.set_icon() is a Pygame function that sets the icon in the window’s title bar (just like pygame.display.set_caption() sets the caption text in the title bar). The single argument to pygame.display.set_icon() is a Surface object of a small image. The ideal image size is 32 x 32 pixels, although you can use other sized images. The image will just be compressed into a smaller size to be used as the window’s icon.