I'm sure there's an obvious quad here somewhere, but I'll be darned if I see it...
{28}{29}{89}{7}{1}{4}{5}{36}{36}
(13}{6}{4}{2}{5}{39}{8}{7}{19}
(7}{13}{5}{689}{69}{38}{19}{2}{4}
(1358}{13}{68}{1568}{467}{2}{147}{9}{13578}
(12358}{29}{7}{1589}{49}{158}{6}{34}{12358}
(1258}{4}{689}{3}{679}{158}{127}{58}{12578}
(9}{8}{3}{15}{2}{157}{47}{46}{567}
(6}{57}{2}{4}{8}{579}{3}{1}{579}
(4}{57}{1}{59}{3}{6}{279}{58}{2578}
Any hints?
thanks.