[AM] (23 december 2004) Here is a little puzzle for the days around Christmas and the Gregorian New Year:

Given a piece of text (where all whitespace has been replaced by single spaces, to make it less ambiguous), such as the description of the [Endekalogue], are there any substrings of given length (longer than, say, 10 characters) that appear at least twice?

Requirements:
   * It should be a pure Tcl script that finds the answer for an arbitrary piece of text
   * It should be "best" in some way

The best solutions are either:
   * the shortest (smallest size of the code for any artistic but consistent definition of ''size'')
   * the fastest (as measured by the [[time]] command)
   * the least number of command executions (as measured by the [[info cmdcount]] command)
   * the most fantastic use of regular expressions 
   * the most obfuscated
   * the most elegant variation on the question (such as presenting a histogram of repeated substrings during the computation ...)
   * the best in any other challenging category 


Rewards for each category: honorary mention on the Wiki 

'''Add your solutions below!'''

''Disclaimer:'' I have no other intention with this contest than the contest itself - it just struck me that I would not know how to solve it using [[regexp]], but I considered the use of regexps for about 10 seconds ....
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