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July 29, 2014: 

Expressions From Integers Version 2  adds an extended version of the original puzzle.  This one has multiple completed input figures and a single target figure with one value missing.   The strategy for this one is to find  an single expression template which will evaluate to the number position containing the  "?".  The same value positions and operations applied in the same order for each figure must equal the "?" position value.   That template applied to the incomplete figure will provide the required value. 

Another puzzle programming exercise from my favorite source: the   Mensa Puzzle-A-Day Calendar.
 

July 23, 2014: Feedback from the May posting of our Logic Solver program and an unsolved Geocaching problem led to Logic Version 5.4 posted today.  Bug fixes include:

1. The "Edit" feature to change variable value names lost rules and facts from the save cases file if they had not been viewed before the changes were made.
2. Rules generated by "Order" rules were not displayed in the  Generated Rules display form.
3. Some text of the Reasons for assigned values to truth truth table entries had column and row references reversed.
4. The big one that took a week to find:  The program implements a syllogism called "Disjunction Elimination" which says that if A implies B,  and B implies C,  and we know that A and C cannot both be true then we can conclude that A is not True.   When applied to "If" statements generated by "Order" and "If"  rules generated a bad fact if the "If" was assign a False value (i.e. "If A then Not B" instead of  "If A then B").  

July 13, 2014:

Well begun is half done!,

StarsOnAGrid implements solving and allowing users to create, modify and  solve puzzles of the  type defined as follows::

Given a square N x N grid divided into N sections, place a star in each section with no two stars in the same column or row, and no two  stars diagonally adjacent to each other.

The program allows grid sizes from 2x2 through 10x10, although no solutions exist for sizes less than 5x5. 
 

June 21, 2014:  Self Describing Sentences, Version 2.2, posted today, adds a few extra examples of self-describing sentences or "Autograms" as Wikipedia calls them.   I also added some run statistics and the ability to interrupt long running cases.  Got to run.  We're off to Kitty hawk and the beach today to spend a few days with daughter and family.

June14, 2014:  Here's a Fill the Blanks Puzzle worth a few idle minutes of your time.  The program makes it easy to validate that your choices are valid words and to explore alternatives.  Another extract from the 2014 Mensa Puzzle-A-Day Calendar.

Many of the 10 given three-letter partial words have more than one choice of final letter to form a common four-letter English word. Use all of the supplied letters exactly once to fill the blanks and complete all these words. 
There is only one solution.

May 28, 2014:  

"Alphabet Long Division" is the 40th sample problem added to the our Brute Force solver download since the original posting in 2001.  It is the perhaps the first problem to extensively test the shorthand feature that treats character strings in equations as multi-digit integers so we can define this problem with equations like BRINK / RIB = RUN,  RIB * R= OAR, etc.   Click the here if you have the April program update and just want this new problem to play with.
 

May 24, 2014: 

Bug Time Trials Version 2 was posted today after scanning to see what robot related programs I have posted.   This is not a very good example but, as usual, playing with it brought a few changes to mind.  The "bug" needs to be maneuvered around a "track" and through some gates in your best time.  Version 2 allows bug size to be adjusted (smaller bug makes it easier and faster to complete the circuit).  I can just break 20 seconds now J.   
 

May 15, 2014:

 We've been busy this month with spring chores (driveway reconditioning, garden preparation, waking up motorized stuff that slept all winter, etc.). 

Tromino Puzzle Solver V1.0 is  a  medium size solver implemented on rainy days and evenings this month: 

One or more copies of the  6 given shapes have been used to tile the grid and then the outlines were removed.  Can you fill them in again? 
 

May 2, 2014:  Another "geocacher" sent me a problem that my Logic Solver program is not solving so far. Several other Geocaching heavy-weights have apparently solved it however.  The problem (in German) can be found at  http://coord.info/GC3NRMZ.  The current Logic Solver update to Version 5.3 has minor updates but the primary reason for the update  to get more eyes to look at the problem to see of there are facts and rules in the description which I haven't picked up on or which the program fails to derive.  A translation of the problem is included in the download files.

April 28, 2014: It has been a productive month for getting spring duties accomplished but not so productive programming-wise.  I spent more hours than care to admit on two programs.  Oscilloscope Version 4.2.4 was posted today with some cleanup of the diagnostics when an input device fails to open for display.  I'll post our Logic problem solver tomorrow along with a problem which the program cannot solve and a request for help. 

April 12, 2014:  Here's another problem solvable by by our Brute Force program which applies exhaustive search matching possible values with variables in a set of equations.   Brute Force Version 3.1 adds the absolute value function, "abs", to equation formats to enable solving the "Billiard Balls" problem.  The problem is to arrange 10 billiard balls into a triangle meeting a set of rules about the balls numbered 1 through 10.  One of the constraints is that the balls in a particular row all have numbers more than 1 away from their neighbors.  This constraint for balls with numbers "a" and "b" can be expressed with the equation "abs(a-b)>1".  Sample problem BilliardBalls.prb is included with the download and is solved in about one second.  
 

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  July 7, 2014:  Note: this "Collapsible"  month by month list of postings since year 2000 is not collapsing for some reason, making this a very large home page.  Until it gets fixed, you can reference the complete quarter by quarter list of postings on the Newsletter page.

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