=== The Bellman's rule ===

001· · "Just the place for a Snark!" the Bellman cried,
002· · · · As he landed his crew with care;
003· · Supporting each man on the top of the tide
004· · · · By a finger entwined in his hair.

005· · "Just the place for a Snark! I have said it twice:
006· · · · That alone should encourage the crew.
007· · Just the place for a Snark! I have said it thrice:
008· · · · What I tell you three times is true."


=== Implementation of the rule ===

The little Haskell program checks whether entries in a list of statements occur three times (or more). Therefore the program is a useful tool to test the truth of statements.