More Puzzling

In a previous post, I discussed my attempt to write a program to solve a puzzle. I never updated that post because, well, I ran the program all night and it didn’t find the solution!

I had made up a fake puzzle that I knew had a solution for testing, and the program could solve it in 15 minutes. But it couldn’t solve the one I had recorded for the real puzzle. I figured (and hoped) that I had simply recorded it wrong and to check, I re-recorded the pieces and tried again. And it worked! Here’s how:

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My mother gave the fam a new game for Xmas called “The Impossible Puzzle.” Or maybe that was the company name. Either way, the label is certainly apt.

The puzzle is composed of nine, 4-sided pieces with interlocking parts in the shapes of the 4 card suits (hearts, diamonds, etc). There is only one way to lock the 9 pieces into a 3X3 square, and the game touts the fact that “there are over 300,000 combinations, only one of which is correct.”

Fig.1: An example of the puzzle pieces.

My mother, her bf, and myself all fiddled with this puzzle for a while before becoming too frustrated. There seemed to be no way to logically sort through the options of all possible arrangements and rotations of the pieces and clearly a brute-force method of trying all combinations would take way too long by hand. But maybe not for a computer. So, I figured this would be an excellent opportunity to try out my programming skills.

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This post discusses a computer program that you can download to try yourself (and get the source code if you want to make your own version).

At a family reunion earlier this summer, we were handed a wordfind that someone had generated somewhere on the Internets that contained the names of the family founders. I was solving mine and noticed that, as anyone has frequently observed, in any given wordfind you will find words that are not in the list. Presumably, this is due to the randomly-assorted letters, by chance, spelling out an unplanned word. Of course, the wordfind makers might also stick those in on purpose (for example, the family wordfind contained the website name multiple times) or purposely prevent some random words (profanity). Regardless, I began to wonder how often a word might appear in a word find just by chance. So I used the margins to scratch out a formula for the chance of finding a word of a certain length within a matrix of random letters.

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A simple model of selection

Inspired by Dawkins’ METHINKS IT IS LIKE A WEASEL program (hereafter just weasel) described in his book “The Blind Watchmaker,” and wanting to practice my blossoming C++ skills, I decided to write my own version of weasel. It was successful enough, and I found the results interesting enough to warrant discussion. Download the program (Windows .exe file) so you can try it out for yourself (and you can also get the source code if you want). In this post I’ll discuss what the program does and why. In the next post I’ll talk a bit about the results of the program.


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