A closed set of dominoes....take any number out from a set of double 6 type (28 set)and join them end to end....o.k... I'll go for ...er 2.3...what are yu left with digit wise on each end? O.K. Ian McLoughlin, Chematek U.K. Tel/Fax : +44(0)1904 679906 Mobile : +44(0)7801 823421 Website: www.chematekuk.co.uk _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers