What's New -  December 2002

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December 20, 2002:  Today we have an updated version of the  Knight's Tour program.  The problem is to place a Knight chess piece on a standard chessboard and move it 63 more times landing exactly once on every square.   I have a new Norwegian friend, a retired science teacher, who  writes good Delphi code for a hobby.  (Meaning he thinks and writes a lot like I do.  <g>)  He pointed out a few omissions  in the  original version including ability to specify a start location for the tour and the ability to generate closed tours.  The final move of a closed tour is positioned so that  the next move could start a repeat of the same tour.   Both features have been added to this version. 

December 17, 2002:  The sum of the cards in the crossbar and in the upright in this T-shaped arrangement is the same.  Can you find 17 more arrangements where this is true?  (Rearranging cards within the crossbar or upright doesn't count, neither does exchanging the roles of the crossbar and the upright).

This "T" Card Sum program will help keep track as you search, and show you the ones you missed.  Another puzzle adapted from one invented by British puzzle maker H. E. Dudeney.

Select 1 or more from any row

December 10, 2002:  Here is a new version of our multi-pile NIM program.  It's a good news-bad news story.  The bad news is, that I didn't realize until finished that I had written an earlier version in April!  This growing old business is going to be heck.   The good news is that at least this version has several new features including ¤ token selection by mouse clicks,  ¤ computer vs. human play,  ¤ miseré (last token loses) play,  and  ¤  improved (.i.e. shorter) implementation of the move selection logic using exclusive or (XOR) operations.   

December 7, 2002:  A viewer was having trouble saving mazes created with our Maze Generator program.   No wonder -  requests that did not include the  .maz file extension were just  ignored.  That  was rather rude,  but it is fixed now.   Who can find the next bug? 

December 6, 2002:  I was browsing Virginia's SOL (Standards of Learning) guidelines the other day and was surprised to see that the Algebra I section has a dozen or so objectives that  specifically require the use of  a graphic calculator.   That prompted me to revisit our SciGraph function graphing program and, of course, ended up fixing a few bugs and making a few enhancements.   Version 1.1 includes help pages with guidelines for writing expressions and previously undocumented  navigation tips.  The mouse can be used to zoom a rectangular area of the chart and to display numeric values of clicked points.  Users are now prompted to save any unsaved chart changes when closing or loading a new chart.   Obviously (to me)  a better choice than a calculator for exploring graphs of functions.   Maybe  if I included  the "Conchoid of Nicomedes", the "Limacon of Pascal", and the "Witch of Agnesi" curves.   Love those names!

December 4, 2002:  Another Martin Gardner trick this week - select one number form each row and column of the Magic Matrix.  The sum will always be the same!    (The big 40 for the sample at right.) This program will not only generate magic matrices for you, but let you play them and understand why they work.