What's New -  June 2004

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June 17, 2004:  Here's a small update to the Scientific Grapher program  with better default values if two series are being plotted and the ability to control the scale of the dependent variable.  I also added Fermat's Spiral to the sample curve files.  

By the way,  it has been reported that practitioners of omphaloskepsis, (contemplating one's navel), use Fermat's Spiral as their symbol.    I'll admit though, that my search for "Omphaloskepsis" images turned up lots of belly buttons, but few spirals.  

June 14, 2004:  I've been trading problems and puzzles with a bright young lady I met at the Destination Imagination Global finals a couple of weeks ago.  She sent me this one  the other day: Insert +, -, x, ÷ symbols into the digits 99999 to make an expression that equals 10.  

It's not too difficult to find one, but I thought she deserved to see all possible solutions.  Besides, I'm trying to convince her programming would be a great career choice.   So here is ExpressionsForBethe, which solves not only this problem but similar problems for any given set of digits evaluating to any given value. 

June 11, 2004:  Here's an update to the Computational Geometry page over in Delphi Techniques section that adds the solution to this problem: .  Given a point and a polygon, determine if the point is enclosed by the polygon.    

How to do it?    Hint: Draw a long line from the red dot in this image in any direction that doesn't pass through any vertices.  Notice that your line intersects an even number of polygon edges.
June 9, 2004:   I uploaded a revised  version today of the DFF Play CD, a file  that contains executable versions of 60+ programs from this site.  I put it together last December for  use in our schools here.   The file includes an autorun  file to start automatically from a CD but will run fine from a hard drive.  There's a loader program, Programload.exe, used  to select programs by category (Science, Math,  Games, Puzzles, Tricks).  If you run it from hard drive or if auto start is not enabled on your PC, start by double clicking  the loader program, .     The zipped  DFF Play CD file  is about 20mb in size.  

 I plan future updates with additions, deletions, and enhanced versions, so pertinent feedback with bugs reports or suggestions will be appreciated as always.  

In the process of updating the CD, I ran across a few typos and minor bugs.  As a result, new versions of Brute Force,  Card Trick, and  Magic Matrix programs have been uploaded.