The director of a government organization shares confidences with nine advisers. To his dismay, however, some of his most intimate thoughts have lately been appearing in newspapers the day after he reveals them. A common technique for discovering leakers is to tell each suspect some unique piece of information (a tidbit) and then see if it spreads. But the director discovers that this approach will not be good enough: news editors will print a story only if at least three advisers attest to the tidbit. He is quite sure there are no more than three leakers.
This article was originally published with the title Plumbers.