#!/usr/bin/perl -w
use strict;
$_= "thisisatest";
print "$_:\n";
while( /(.)(?=(.))/g ) {
    print substr( $_, 0, pos($_)-1 ),
        $2, $1, substr( $_, pos($_)+1 ), $/;
}
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Rewording the description in a manner that helped at least one person understand: Take a string, pick any pair of consecutive letters in the string (at random), swap them. What is the list of all possible results?

                - tye