April 30, 2018

Spring has sprung,
The grass has riz,
Where last year's
Careless driver is!
Burmashave

My mysterious mind remembers this roadside Burmashave sign from 70 years ago but forgets what I had for dinner last night!

Here are the 2018 postings to date:    

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January 3, 2018:  Happy New Year!    Here's an interesting history clip from  the  SourceForge website today:

Today in Tech – 1983

On this day in 1983 TIME magazine named its first Machine of the Year: the personal computer. It was a deviation from their annual tradition of naming Man of the Year, but was an appropriate one. At that time the PC was making big strides and a big impact on the world at large. As TIME publisher John Meyers wrote: “Several human candidates might have represented 1982, but none symbolized the past year more richly, or will be viewed by history as more significant, than a machine: the computer.” The PC remains the first and only Machine of the Year that TIME magazine has ever named.

Cube

Sphere

Figure

Football Field

January 18, 2018:  3D Lab is an interesting program which draws one of several sample 3D objects viewed from multiple angles and elevations under user control.  Even though the code is 20 years old, it implements the math behind virtually all of today's CGI productions. Much of  the code here is likely  implemented in hardware today.   Thanks to Earl Glynn for publishing the original program and for permission to re-post it here with a little  animation of figure rotation.

February 5, 2018:  

Cats love to chase mice, pirates love to chase merchant ships, and dogs love to chase rabbits. I recently received an interesting book titled "Chases and Escapes", (Paul Nahin, Princeton University Press). The math gets a little heavy (i.e. Differential Equations), but the initial approach, the "Pursuit Curve" illustrated here, is straight forward and fun to simulate. The Dog chases the Rabbit by always heading toward its current location. If the dog runs faster than the rabbit (and the field is large enough), he will always achieve his go    al.  This rabbit has a hole where he's safe if he can run at least as fast as the dog. In this Pursuit A program you can control the speed and the dog's location when he spots the rabbit and starts the chase.  Lots of room here for enhancing this program or adding other chase strategies.   
 

February 11, 2018: 

Of the 450+ programs on DFF,  Wordstuff is one of the two that have earned places on my desktop.   BruteForce, an integer algebra solver is the other. These are the "go to" programs when I need help with our Daily Mensa^© Calendar puzzles.

Wordstuff is a "wrapper" for six programs solving or helping word based puzzles.   Over the years, many bug fixes have been applied but enhancements can introduce new ones.  Updates today fix annoyances in the Word Completion and Unscramble sections.  Use the link above for more details and to download the program if interested.
 

March 15, 2018:  A few years ago, someone came looking for Delphi code to allow highlighting specific words in a DBGrid (database grid) control.  I  don't use DBGrids, but StringGrid controls serve as a good substitute, or so I thought.  One of the StringGrid features not available in DBGrid was originally used to expand column widths when highlighting text size.  Code was changed to eliminate use of hat feature, but the unused code remained in place.   A fellow programmer wrote last week informing me of the problem when converting to use a DBGrid.  GridWordHighlight Version 1.1 posted today, removes the offending code and should work for either grid type. 

March 26, 2018: 

Here's the February 23 Mensa puzzle that resulted in No Close Neighbors Version 3.0   posted today.  Two added features for this puzzle (duplicate letters and unfilled cells) make it several times more difficult that the original.  It's only slightly more difficult for the computer program to solve, but much harder for humans trying  to solve it manually or for the programmer trying to tell the program how to do it (me!).

The original puzzle did not allow repeated letters and told you where the unused cells laid.  This puzzle changes that.  If you're up for a challenge, check it out.  

 

April 29,2018:

Here's a  "Telephone words" program that converts number strings into words based on standard keypad number-to-letter assignments as illustrated here (e.g. 364 ==> DOG).

Businesses like phone numbers that can be presented as words with the idea that they are easy to remember.   I (and probably most callers) dislike them because it slows and complicates the dialing process.   But they do make interesting puzzles!.  

One problem with real phone number is that they include "0"s and "1"s which have no associated letters. I ignore "0"s and use '1"s as space characters, allowing multi-word encoding.

One other problem when using numbers to encode messages is that there may be multiple  translations. For example,46631364 not only decodes to:"GOOD DOG" but also to "HOOF FOG" and 12 other variations.  For what it's worth, this program finds them all. 

 

 

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Quotes from past Newsletters (continued):

DFF News #30,  December 11, 2002:  "Success in solving the problem depends on choosing the right aspect, on attacking the fortress from its accessible side." - George Polya, Mathematician 

DFF News #31,  February 28, 2003: "I have failed over and over again in my life.  And that's why I have succeeded."  Michael Jordan (basketball player)

DFF News #32,  May 24, 2003: "It is not knowledge, but the act of learning, not possession but the act of getting there, which grants the greatest enjoyment. When I have clarified and exhausted a subject, then I turn away from it, in order to go into darkness again." - Karl Friedrich Gauss (Mathematician) 

DFF News #33,  August 3, 2003 : "Every problem has in it the seeds of its own solution.  If you don't have any problems, you don't get any seeds..." -- Norman Vincent Peale
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