example S [0, 3, 4] X [[1, 2, 3], [1, 2, 4], [0, 3, 4]] b= 7 no colouring: True every 6-subfamily colourable: True
example S [2, 3, 4] X [[2, 3, 4], [1, 2, 3], [0, 1, 4]] b= 7 no colouring: True every 6-subfamily colourable: True
