Python 3 code
##################################################################
# 2D Julia set generation by a cellular automaton (c = 0.7454294)
# (graphics module)
##################################################################

# mod graphics in /Users/strumia/Library/Python/3.6/site-packages/graphics/
import sys
sys.path.append("/Users/strumia/Library/Python/3.6/site-packages/graphics/")
from graphics import *      # import graphics module

Radius = 30   # set escape rate threshold
Cx = 0.7454294     # set c  parameter real part value
Cy = 0.0      # set c  parameter real part value
Side = 1.7     # set square area side
M = 300   # set side number of elementary squares
N = 1   # set color map scale factor
Num = 256*N   # set number of cycles
sT=5    #  set step jump
w = 0   # set starting escape modulus value
x = 0.0  #set x co-ordinate initial value
y = 0.0  #set y co-ordinate initial value

import random   # import random module

p = M/2+random.randrange(-M/2,M/2)
q = M/2+random.randrange(-M/2,M/2)

win = GraphWin("Julia set", int(5*M/3),int(5*M/3))

def rectCol(p,q,w):
   Rect = Rectangle(Point(int(p-sT/2),int(q-sT/2)),
   Point(int(p+sT/2),int(q+sT/2)))
   Rect.draw(win).setFill(color_rgb(int(10*w%255),
   int((128-10*w)%255),int((128+10*w)%255)))

# Alternative values Cx 0.1747, 0.1747 Cy -.072,-1.072
# Side 0.0015, 0.00015 Num 1024

i = 1   # set non-zero index value
while i > 0:    # set random co-ordinates choice cycles
   p = p+random.randrange(-1,2)*sT
   q = q+random.randrange(-1,2)*sT
   if p < 0:
     p = p+2
   elif p > M:
     p = p-2

   if q < 0:
     q = q+2
   elif q > M:
     q = q-2

   Incx = - Side + 2*Side/M*q
   Incy = - Side + 2*Side/M*p
   x = Incx
   y = Incy
   w = 0
   for n in range(1,Num):
      xx = x*x - y*y - Cx
      yy = 2*x*y - Cy
      x = xx
      y = yy
      if x*x + y*y > Radius:    # escape rate condition
         w = n/N
         rectCol(int(M/3+q),int(M/3+p),int(w))
         break

win.getMouse()
win.close()