Help Google adding correct street numbers in maps

I stumbled upon a nice way of distributing tasks implemented by Google. It's about street numbers, which in most of the navigation applications are problematic. Google is trying to fix this by giving you this refined CAPTCHA mechanism:

Each time you post to a blog comment you get this CAPTCHA (if you get it).

I imagine that these images are in a database which associates them to:

* street
* gps coordinate
* direction (left/right)
* ...

I completed with a wrong number and got no complains :)

Happy mapping Google!

Which image looks more messy?

Created with this dumb python script:

#!/usr/bin/python

import random
import sys

def write_pgm(filename, width, height, buf):
    header = "P2\n#%s\n%d %d\n255" % (filename, width, height)

    f = open(filename,"wt")
    f.write(header)

    bufsize = len(buf)
    for i in range(bufsize):
        if i % width == 0:
            f.write("\n")
        f.write( "%03d " % (buf[i]) )

    f.close()


if __name__ == "__main__":

    random.seed()

    w=320
    h=240

    stains=32

    # uniform mess
    buf=w*h*[0]
    for i in range(stains):
        n = random.randrange(w*h)
        buf[n] = 255

    write_pgm('uniform.pgm',w,h,buf)

    # concentrated mess (only the upper part)
    buf=w*h*[0]
    for i in range(stains):
        n = random.randrange(w*h/10)
        buf[n] = 255

    write_pgm('concentrated.pgm',w,h,buf)