The listener letter last week asked about the the three "red dots" that are used to identify liquor stores in South Carolina.Turns out that this kind of "shibboleth" is a way of identifying and discriminating, in ways that can be useful, or harmful.Red Dots in South Carolina:The Robert Moss (SOUTHERN SPIRITS) versionSouth Carolina Encyclopedia (from Moore, John H. “Solving the Red Dot Mystery.” Sandlapper,  spring 2000: 32–34.)ShibbolethGileadites and EphraimitesBackground on the conflictThe Stone Signposts of PompeiiWorld Series as Shibboleth  (Robert T. Gravlin, 23rd Armored Engineer Battalion)Appropriate Measures of InflationIf you have questions or comments, or want to suggest a future topic, email the show at taitc.email@gmail.com ! You can follow Mike Munger on Twitter at @mungowitz