Odd-even

Rules:Draw a single closed loop passing through all the cells exactly once.The loop cannot intersect itself or branch off.The loop must turn in every outlined region.The loop alternates between odd and even number of turns when it passes through different outlined regions.In other words, if the loop enters region B immediately after leaving region A,and enters region C after that,it turns even(odd) number of times in A and and odd(even) times in B.
An example is shown below.