K. 128. The starting position of a logical game is shown below:
The pieces marked with arrows are moving. Every piece may move in the direction indicated by the arrow on it: it may either move to the adjoining vacant field or skip to the next field over any piece in the adjoining field, provided that the next field is free. The task is to make the counters marked with the two kinds of arrows exchange places. Draw the sequence of moves to achieve the exchange.
This problem is for grade 9 students only.
Deadline expired on 10 October 2007.