Question 7 has a simpler solution: rule 1 and 3 can be combined that the arrow points to South, East, North and West (i.e. rotates anticlockwise 90 degrees each time). According to this rule and rule 2 in your answer, we can have the correct answer faster.
楼主: locust_j
/1 
发表于 2017-8-19 18:37
