Dear pi314159265,
You are thinking of a Mathematical Recreations column by Martin Gardner
that I have read myself. I can look up the exact volume and issue numbers
at my university tomorrow, if you like, but it won't help you unless you
also have access to decades-old back issues of Scientific American. The
column is copyrighted material, and SciAm's online archives extend back
only as far as 1991. Gardner's column appeared much earlier than that.
As an alternative, you may wish to order a book that explains the secret
behind this puzzle and many of its variants. In Gardner's Mathematics,
Magic and Mystery, Chapters 7 and 8 are devoted to puzzles of this
kind. The book is published by Dover and sold by Amazon at a modest price.
Dover Publications: Table of Contents for Mathematics, Magic and Mystery
http://web.doverpublications.com/cgi-bin/toc.pl/0486203352
Amazon: Mathematics, Magic and Mystery (Cards, Coins, and Other Magic)
by Martin Gardner
http://www.amazon.com/exec/obidos/ASIN/0486203352/qid=1113134800/sr=2-1/ref=pd_bbs_b_2_1/104-6123063-2132734
Although this general class of puzzle is known as a geometrical vanish
or a vanishing puzzle, the form in which many of us first encounter
it, as you did, is the increasing puzzle. Here, a square of 8x8 = 64
units is transformed by cutting and rearrangement into a 5x13 = 65-unit
rectangle. The increasing puzzle in reverse is, of course, a vanishing
puzzle. The following page features an interactive Java animation of
the classic increasing puzzle.
Cut the Knot: A Faulty Dissection
http://www.cut-the-knot.com/Curriculum/Fallacies/FibonacciCheat.shtml
More coverage is provided here.
University of Surrey: Ron Knott: A Fibonacci Jigsaw puzzle or How to
Prove 64=65
http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/fibpuzzles2.html#jigsaw1
Another page illustrates with great clarity that the extra square's worth
of space is accounted for by a narrow gap running along the diagonal of
the rectangle.
Jim Loy: The Extra Square
http://www.jimloy.com/puzz/missing.htm
Interestingly, the 8x8 dissection can also be rearranged into a shape
whose area appears to be only 63 units in area.
Cut the Knot: Sam Loyd's Son's Dissection
http://www.cut-the-knot.com/Curriculum/Fallacies/SamLoydSon.shtml
Finally, you may be amused by another vanishing puzzle in which a triangle
appears to lose one square unit's worth of area after rearrangement. Do
you see where the missing square has gone? It took me quite a while to
work this one out.
Cut the Knot: How Can This Be True?
http://www.cut-the-knot.com/ctk/BeTrue.gif
It has been a pleasure to address this question on your behalf. If
you have any concerns about my answer, please advise me through a
Clarification Request so that I may attend to your needs before you
assign a rating.
Regards,
leapinglizard |
Clarification of Answer by
leapinglizard-ga
on
12 Apr 2005 19:56 PDT
In the May 1961 issue of Scientific American, one of the puzzles in
Martin Gardner's column is a geometrical vanish in which both the
original and the rearranged shape have the outline of a square, but
one of them has a hole in the middle. I'm certain there are other
Martin Gardner articles featuring such puzzles, given that they are a
recurring theme in his books. Could the May 1961 issue be the one?
If not, can you give me some idea of when you read the article, say
within a range of five or ten years? It would help a great deal with
the search. By the way, I have taken a look at the book chapters I
recommend above and they contain an awful lot of information about
these kinds of puzzles. If you're interested in the mathematics behind
them, I'm certain you'll be glad to own the book.
leapinglizard
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