All this fidding with bits in the Thread "How to get non-unique
elements from an array" got me digressing to search engines and
indexing.

 So if you have for example

 Doc1=The quick brown fox

 Doc2=Jumped over the brown dog

 Doc3=Cut him to the quick

 You can build a table with bit number and word.

  1 the
  2 quick
  3 brown
  4 fox
  5 jumped
  6 over
  7 dog
  8 cut
  9 him
 10 to
 11 quick

 To create indices

 Doc1=00000001111
 Doc2=00001110101
 Doc3=11110000011

 You can very quickly return the Docs that contain 'the' [
Doc1,Doc2,Doc3 ], or brown [ Doc1,Doc2 ] etc.

 The rubyquiz idea would be to write a simple indexer/query system.

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