Compass theme

The black King and two black pieces alternatively occupy two squares X and Y in a 4-solution helpmate in two. The distribution of the occupation of the two squares X and Y may take several possible cardinal directions and it is helpful to use a compass to identify in which geographic zone the occupations are made by the black King and the black pieces. For more information see the article: http://onkoud.com/wp/wp-content/uploads/2018/06/Le-thème-de-la-Boussole-Conférence-Belgrade-2016.pdf