 unique [5]? b) is the partial
 unique [5]? b) is the partial  -geometry with nexus three and blocksize
 -geometry with nexus three and blocksize  unique [2]? c) is there a unique graph such that it is the graph of a parallelism of
 unique [2]? c) is there a unique graph such that it is the graph of a parallelism of  with respect to any [1]? We observe that these questions are equivalent and give an affirmative answer. In fact, we prove a more general theorem, showing the truth of a conjecture by Cameron.
 with respect to any [1]? We observe that these questions are equivalent and give an affirmative answer. In fact, we prove a more general theorem, showing the truth of a conjecture by Cameron.