here is the modified program used to generate the childrens' game output in red and blue.
import pylab
import random
import math
x_inner, y_inner = [], []
x_outer, y_outer = [], []
for attempt in range(10000):
    a, b = random.uniform(-1.0, 1.0), random.uniform(-1.0, 1.0)
    if math.sqrt(a**2 + b**2) < 1.0:
        x_inner.append(a)
        y_inner.append(b)
    else:
        x_outer.append(a)
        y_outer.append(b)
pylab.scatter(x_inner, y_inner,c= 'red', marker = '.', s=200)
pylab.scatter(x_outer, y_outer,c= 'blue', marker = '.', s=200)
print 4*len(x_inner)/float(len(x_inner) + len(x_outer)), math.pi
pylab.axis('equal')
pylab.title("children's game, with color code for pebbles")
pylab.savefig('direct_pi_color.png')
pylab.show()