This web site is mainly devoted to BIBDs, Nested BIBDs, OBIBDs and Nested OBIBDs. It will include informal constructions and properties of these designs, examples, and non-exhaustive lists of designs, from searches (including the order of the automorphism group, where possible.) It is intended to reflect my own interests, and not as a rival to any other such: it is not a didactic tool, things will be included or excluded as the spirit moves me. None of it has been refereed, and while I have tried to ensure its correctness, it is unlikely to be totally free of error ;-)

In many cases, I do not know whether the results given here are original or not, as I live in a very complicated world: if anyone objects that he/she should be given the credit for something given here, let him/her email me with the details and I will try to do him/her justice. In any case, use them at your own risk!

Some references are given, but I cannot guarantee that all relevant ones are listed.

I don't at present (June 2016) intend to add anything to the website, apart from some tinkering. Access to the website is intermittent, reflecting the changing commercial scene (the original Freeserve has passed through several hands, and the original concept of a free service is hard to maintain in a very competitive world). Even so, I don't think I am going to replicate this website elsewhere.


The automorphism groups were calculated with the aid of the set of procedures nauty (the previous version), downloadable from here, written by B.D.McKay. Responsibility for the correctness of the results, as of everything else, rests with me.

Details of groups are as given in GAP. Again, any errors arising in their use are my responsibility.

I have removed the email link because I am getting so much junk email (based, I assume, on automated scanners): those who wish to contact me can try my Apple iCloud address. put a dot between the "david" and the "hywel", and then add the appropriate icloud suffix.

Site last updated: 12th June 2016

By D.H.Rees