[pygame] Some help, please...

["Adeola Bannis" <thecodemaiden@xxxxxxxxx>]

Hi all,
I am writing a snake game, but all is not going well...

Two problems here. First of all, the little circles I use for my sprite
images only show up as quadrants.
Second of all, only the Head sprite for my snake shows up at all. Why?

Here are the class definitions:

! /usr/bin/python

import pygame as PG

seg_size = 20

class SnakeSegment(PG.sprite.Sprite):

        def __init__(self, pos):
                PG.sprite.Sprite.__init__(self)
                self.image = PG.Surface([seg_size,seg_size])
                self.rect = self.image.get_rect()
                self.rect.topleft = pos

#               self.direction = 0

class SnakeHead(SnakeSegment):

        def __init__(self,pos,spd = 10):
                PG.sprite.Sprite.__init__(self)
                SnakeSegment.__init__(self,pos)
                PG.draw.circle(self.image,(255,0,0),self.rect.center,4)
                self.speed = spd # governs speed of whole snake

        def update(self):
                self.rect.left += self.speed

class SnakeBody(SnakeSegment):
        def __init__(self,pos,prev):
                PG.sprite.Sprite.__init__(self)
                SnakeSegment.__init__(self,pos)
                PG.draw.circle(self.image,(0,255,0),self.rect.center,4)

                self.previous=prev
        def update(self):
                self.rect.center = self.previous.rect.center

class SnakeTail(SnakeSegment):
        def __init__(self,pos,prev):
                PG.sprite.Sprite.__init__(self)
                SnakeSegment.__init__(self,pos)
                PG.draw.circle(self.image,(0,0,255),self.rect.center,4)

                self.previous=prev

        def update(self):
                self.rect.center = self.previous.rect.center

class Snake(PG.sprite.OrderedUpdates):

        def __init__(self, pos, length = 6):
                PG.sprite.OrderedUpdates.__init__(self)
                self.head = SnakeHead(pos)
                self.segs = length - 2
                self.position = pos

                self.add(self.head)

                prev = self.head

                posx, posy = pos

                for x in range(self.segs):
                        posx += seg_size
                        prev = (SnakeBody((posx,posy),prev))
                        self.add(prev)
#                       print prev.rect.center
                posx += seg_size
                self.add(SnakeTail((posx, posy),prev))
                self._spritelist.reverse() # we need tail first, head last

Whew!
And here is my little test program.

#!/usr/bin/python

from snake import *
#import pygame as PG
DBUF = PG.DOUBLEBUF
FSCR = PG.FULLSCREEN
screenx = 640
screeny = 480

def main():
        PG.init()

        screen = PG.display.set_mode((screenx, screeny)) #python likes to make
pointers.

        q = Snake((100,100))
        q.draw(screen)
        q.update()
        PG.display.flip()
        while 1:
                PG.event.pump()
                keyinput = PG.key.get_pressed()
                if keyinput[PG.K_ESCAPE] or PG.event.peek(PG.QUIT):
                        break

if __name__ == '__main__':
        main()

Whoop, there it is. What have I done wrong?