import random
def conflict(state,nextX):
    nextY=len(state)
    for i in range(nextY):
        if abs(state[i]-nextX)in (0,nextY-i):
            return True
    return False
def queens(num=8,state=()):
    for pos in range(num):
        if not conflict(state,pos):
            if len(state)==num-1:
                yield(pos,)
            else:
                for result in queens(num,state+(pos,)):
                    yield (pos,)+result
def prettyprint(solution):
    def line(pos,length=len(solution)):
        return '.'*(pos)+'X'+'.'*(length-pos-1)
    for pos in solution:
        print(line(pos))
        
prettyprint(random.choice(list(queens(8))))
