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The index page for all Programs on the site?

The DFF Play CD?

Zipped file DFF Play contains  executable version of about  75 of the 200+ programs from the site, mostly those I particularly liked or thought would be of widest interest for non-programmers.  The file is rather large, about 20mb..

Anything else?




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Not a programmer (yet)?

 That's OK -  the executable version for any puzzle or  game you find here is available for download.  Just scroll down to the bottom of most any description page and you'll find a "Download executable" link. Downloaded programs are in "zipped" format to reduce size and may require an "unzipper" program unless you are running Win XP or later.  Here's a link to a free one. 

Check  out  the Most Popular  Downloads from DFF   (updated weekly)

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Take a look at the Introduction page to see what this site is about

Notes for Teachers


What's New

November 13, 2015:


6th grade Algebra?

 Brute Force is our  program which solves many algebra based puzzles with integer solutions. It works by exhaustive search over a set of values, trying all combinations in a set of equations.  A viewer recently reported having a problem solving this equation set which he described as a "6th grade level algebra problem".   Not in my 6th grade!   In any event, the program couldn't find a solution with a trial digit range from 1 to 30.  That is, until I increased the maximum number of trial digits from 20 to 50.   Brute Force Version 3.4.1 posted today implements the change and finds the solution 5 seconds!  It now also warns if you specify a range larger than 50 numbers,  Sample problem Test50.prb is the  problem that uncovered the bug and is included in the downloads.   I'm off to try my high school solving skills on this problemJ.


November 12, 2015:  At least for me, Microsoft made the Windows file search option virtually unusable when they rewrote it for Windows 7.    It's a function that I rarely need, but when I do, I don't want to search help or the internet to find how to do it.  This week, I finally wrote a FastFileSearch program to find files meeting masking criteria from a selected start folder (e.g. find *permut*.exe to list all permutation related programs in my DFF folder).   No content searching yet, but that enhancement is in the wings if I need it.  Maybe Windows 10 search will work, but when last I checked ,the Win10 Edge browser did not support  add-ons and the Win32Help program could not be installed.  Both of those deficiencies are deal breakers for me.           

October 29, 2015:

Last Sunday's Mensa Calendar Puzzle led me to dig out the Self Describing Sentences program written several years ago.  Sure enough it can solve this one, but I can't revisit a program without finding some bug or desired enhancement.  This time I added the ability to count the number of consonants in a self describing manner.  Self Describing Sentences Version 2.3 was posted today.  

November's big project is a program to approximate the largest rectangle that can be drawn inside of an arbitrary polygon.   A patient user requested it a few months ago and it does sound like an interesting challenge.  

October 19, 2015: 

Complete this grid with 10 different words using the given letters

I recently discovered the was a perfectly good name already defined (Double Word Squares) for  what I had been calling "Square Word Grids" to distinguish them from the symmetrical "Word Squares" puzzles.    Double Word Squares Version 3  posted today has several major enhancements and has occupied my spare time for the past 8 weeks!  I will admit that the "fun level" decreased during the period and I reverted to "never give mode" several times.  The resulting product still needs polishing, but I believe that it mostly works.  Please let me know if you find otherwise.    The changed and new features include a revised search algorithm and revised user interface.  It now takes less than a second to solve this Mensa Puzzle which the previous version could not solve in over 10 hours of run time! 

October 2, 2015: 

Late last year, curiosity led me to investigate how license keys  or serial numbers might be created.   Activation procedures requiring name, email address or other personal information lead me to believe that the assigned key contains data used for verifying that the user is the owner.    A user recently uncovered a couple of bugs when a larger number of fields or special characters are included.  License Key Demo Version 1.2 corrects these and a couple of others discovered during testing, 

September 24, 2015:  A fellow Delphi programmer recently inquired about writing code to control the master volume level on a Windows PC.  I searched online and found the key unit (MMDevAPI) connecting the Delphi code to the Windows internal volume control routine online.  Here's a Master Volume Demo which includes the MMDevAPI unit and a demonstration program  to verify that it works.

September 20, 2015:  

We  have more trees on our property than I can ever use for firewood.  A small sawmill has long been on my wish list, but its cost makes it a toy that's hard to justify.  A horizontal band mill   (bandsaw laid on it's side and mounted on a track) is the most common type for small operators and prices start at a few thousand dollars.  For this mill type, logs lie on the bed and are rotated as required to cut boards and beams.  As a substitute for a mill, I wrote a program several years ago to display log sawing patterns for use on on my non-existent horizontal band mill.  Requests from two real saw mill owners this week led me to revisit the program. Log Saw Patterns V1.2 posted today fixes a small bug which subtracted blade thickness twice for some cuts when cutting around a fixed width cant.  I also added the ability to  save and reload setup parameters by name reference.  The guys have more good ideas for improvement which will appear in a future version.

September 13, 2015:  The anagram feature of the Word Completion section of our Wordstuff wrapper program  was preciously only available if no words were found when filling a single missing letter.  A recent puzzle required finding anagrams even when there were words found without anagramming.  Word Completion Version 2.3 adds a check box to force anagram searches in either case. 

September 8, 2015:  No joy yet on the Double Word Squares Solver described last time.  In the meantime though, today's calendar puzzle is a logic problem about 3 girls and the ordering of number of train rides taken and countries they visited.  I worked on it for about 15 minutes before deciding to revisit my Logic Problem Solver program.  Another 15 minutes entering the problem and encoding the facts and rules produced the solution.  The problem is now included in the Logic Solver downloads as Girls_Visiting_Europe.prb.  The program by default runs in User mode, providing you with the problem and variable names and possible values predefined.   It's up to you to enter facts and rules  using program templates.  (For example: from the given statement "Betty has not taken the most train rides", we can deduce and enter the fact "Betty isn't T3" where T3 is shorthand for the person with the most train rides.)    The program's "Author" mode will give you the 3 ffacts and 2 order rules that I fed the program to produce the solution. 

 August 30, 2015:

Complete this grid with 10 different words using the given letters

 I have been working without success on an upgrade to our Square Word Grids program to improve the search algorithm for 5x5 double word squares.  "Word Squares" are N x N square word grids consisting of the same N words each containing N letters running horizontally and vertically.  "Double Word Squares" are similar except that the words in each direction need not be the same. The program search for the solution to the puzzle  illustrated here  ran for 10 hours without success.  My September project will be to crack this nut.  

 In the interim, I updated the "Crossword Helper" (aka "Word Completion")  to version 2.21 to allow completing partial words using only letters provided. This allowed me to complete this puzzle with a little extra effort.  The Wordstuff wrapper download includes the revised Crossword Helper program.       

August 23, 2015: Most of this month has been spent on outdoor activities.  Due to generous rainfall and moderate temperatures this summer, trees and shrubs have tried to take over driveways, trails and yards.  With my trusty chainsaw and a new wood chipper, I have almost broken even in reclaiming the space that nature is trying to confiscate.   Of course, she will always win in the long run. 

Which reminds me, my book-of the-month is  The Canon by Natalie Angier.   It really is "A Whirligig Tour of the Beautiful Basics of Science".. She is something of a wordsmith, but the knowledge conveyed here reminds us of what an infinitesimal part of the universe we represent.  For example, our rather small sun is one of billions but still converts 700 million tons of hydrogen to helium every second, has done so for 5 billion years, and will do so for 5 billion more before it runs short of fuel and  starts its expansion to a giant red star!    Highly recommended.

Of course, I have also kept up this month with the daily Mensa Calendar puzzles.  Here's an interesting one from August 18, which can be solved with the aid of our Brute Force algebraic equation solver.

Nine Knights numbered 1 through 9 are seated at the Round Table in such a way that every knight's number is at least 3 higher or lower than its adjacent neighbor. Also, the two knights at the end of the horizontal line sum to an even number. With knights 2, 6, and 8 seated as shown, seat the rest of the knights,

The unique solution can be found by assigning variables to the missing positions and defining equations using Absolute Value (abs) and Modulo (mod) functions.  The puzzle file is now included in the Brute Force downloads as Mensa-08-18-15.prb


July 28, 2015: A fellow Delphian recently asked if it was possible to highlight a particular word wherever it occurred  in a DBGrid. I gave him some suggestions but didn't hear, back so I decided to try it for myself.  I used a StringGrid to create a demo in our Delphi Techniques section which should transfer to DBGrids.  As usual (and thankfully), there were a few unexpected complications  to sharpen problem solving skills and keep programming fun.  Check out the GridWordHighlight page for more information and downloading the code. 

July 17, 2015: A couple of years ago I posted a bulk Find and Replace program which would scan text files in a given folder which match  given file name mask and change all occurrences of a given string to a new replacement string.    I recently needed to process a set of files of email addresses and replace all "@" characters with commas (",") so that Excel could automatically break out the website address parts into a separate column.  The files happened to be in Unicode character format (2 bytes per character) which my program didn't handle correctly.  Find and Replace Version 2  posted today corrects that.  Both ANSI and Unicode character files can now be processed correctly.      

July 8, 2015:

Chess PGN (Portable Game Notation) is a widely used format for recording chess games for historical or study purposes.  There are many playback programs available and the world didn't need another.  However a DFF viewer requested it about 10 years ago and I couldn't locate an existing one in Delphi, and it sounded like  (and was) an interesting project.  Chess PGN Version 5,2 posted today has a small change which doesn't change the executable results but prevents aborted execution after recompiling with data range checking.


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