Rodolfo Marcelo Kurchan asked: What is the smallest number of chess queens that can be placed in an n-cube so that all unoccupied cells are under attack by at least one queen? My best attempts for cubes of orders 3 to 9 are 1,4,6,8,14,20, and 24, respectively. Can anyone do better? (Journal of Recreational Mathematics 21 (1989), p. 220, #1738) APH