a python brute force solution to https://www.behance.net/gallery/32501799/Puzzlebot

puzzlebox.py

class Constraint(object):
	def __init__(self, guess, lights):
		self.n = guess
		self.l = lights
		self.g = sum(1 if c is 'g' else 0 for c in lights)
		self.r = sum(1 if c is 'r' else 0 for c in lights)
		
	def consistent(self, m):
	  # given m as 'true', return true iff this constraint would have come about from m
		in_place = [v[0]==v[1] for v in zip(m, self.n)]
		# since in-place (green) has precedence, check it first and remove it from m and n
		# (what's left is n_remain compared against m_remain)
		n_remain = [v for (p,v) in zip(in_place, self.n) if not p]
		m_remain = [v for (p,v) in zip(in_place, m)      if not p]
	  # count number of out of place but correct numbers (i.e. caused red lights)
		out_of_place = 0
		for i,v in enumerate(n_remain):
			if v in m_remain:
				out_of_place += 1
				m_remain[m_remain.index(v)] = -1 # must set to -1 so 00 cannot match twice to 01, e.g.
		return sum(in_place) == self.g and out_of_place == self.r
		
if __name__ == '__main__':
	import itertools
	# init 'constraints' (previous guesses and the resulting lights)
	guesses = [[2,5,4,9],[0,4,2,4],[3,8,1,6],[5,0,0,4]]
	lights = ['g...', 'rrr.', '....', 'gr..']
	constraints = [Constraint(guesses[i], lights[i]) for i in range(len(guesses))]
	# init list of all possible 4-digit tuples
	all_m = itertools.product(*([range(10)]*len(guesses[0])))
	# filter down to only the tuples consistent with each constraint
	for c in constraints:
		filtered = [m for m in all_m if c.consistent(m)]
		all_m = filtered
	# print the result
	print all_m