Words & Stuff
                                      
B: Draws Cab

   (13 July 1997)
   
   There are plenty of words which turn into other words when spelled
   backward. (No, not when spelled "backward," smart-aleck. When the
   order of the letters is reversed, okay?) "Straw" turns into "warts,"
   "mart" into "tram," "room" into "moor," "reward" into "drawer." More
   unusual -- or at least less commonly discussed -- are words I call
   "switchbacks": words which turn into other words if you change one
   letter (to any other letter) and then reverse the order of the
   letters.
   
   For instance:
   
   elf < -- > fly
   bird < -- > drab
   deal < -- > land
   door < -- > road
   flaw < -- > waif (or wolf)
   liar < -- > rain
   
   As with ordinary backward words, shorter switchbacks tend to be less
   interesting. It's fairly easy to find three-letter switchbacks, such
   as "now" (becoming "wow" or "wen") and "tea" (becoming "art") --
   you're changing one-third of the letters as you do the reversal. But
   four-letter switchbacks ("work" or "word" becoming "prow") are a
   little harder to find, and five-letter ones (or longer) are even
   harder. Here are a few:
   
   adobe < -- > ebola
   deter < -- > rated
   dwarf < -- > fraud
   lemon < -- > novel
   lions < -- > snail
   names < -- > semen
   paper < -- > recap
   
   Note that the switchback process can never re-produce the original
   word. Changing two letters and reversing could take a near-palindromic
   word like "never," change the first and last letters to make "reven,"
   and reverse to obtain the original word. But if you compare a word
   with its reversal, they always differ either in no letters (if the
   word is a palindrome) or in at least two letters; changing exactly one
   letter can never turn a word into its reverse.
   
   There's a word-ladder game that many logophiles enjoy (Lewis Carroll
   was a well-known practitioner), involving turning one word into
   another word by changing one letter at a time, with each intermediate
   step also being a word. For instance, you can bring home the bacon by
   changing WORK into MEAT one letter at a time: work, fork, folk, fold,
   mold, meld, melt, meat. (By the way, you can sometimes turn a word
   backward by changing one letter at a time -- you can change [1]WARD
   into DRAW, for instance, in eight steps...) You can make the same
   sorts of ladders with switchbacks: NAVES, for instance, to SEVEN, to
   NEVER, to RAVEN. I don't know of any switchback ladders longer than
   four steps, but I haven't looked very hard.
   
   My favorite switchback is the first one I came up with, back in high
   school: I noticed that if you turn "flowered" backwards and change one
   letter, you get "werewolf." Who ever said Dungeons & Dragons® wasn't
   educational?
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   Addendum: I've written a [2]Perl program that takes a word as input
   and (by brute force) checks all switchback possibilities to see if
   they're words, by looking them up in a given word file (like the
   /usr/dict/words file often found on UNIX systems). Note that this
   program is probably not the most efficient method of finding
   switchbacks, but it does seem to work. (Note particularly that if you
   run it on a system with other users, you probably ought to set it up
   to avoid hogging processor time, by using the nice utility or
   something.) Commentary and improvements are welcome. (One more note: I
   didn't use this program to find any of the above switchbacks.)
     _________________________________________________________________
   
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     _________________________________________________________________
   
   [3]Reader comments page
     _________________________________________________________________
   
   
    [4]Jed Hartman <[5]logophilia@kith.org>

References

   1. http://kith.org/logos/words/upper/B.answers.html
   2. http://kith.org/logos/words/upper/B.switchback.pl
   3. http://kith.org/logos/words/upper/B.comments.html
   4. http://kith.org/logos/home.html
   5. mailto:logophilia@kith.org