Pebbling a Checkerboard Game

I happened upon this tweet when I got to work this morning:

So I watched the fantastic numberphile video Pebbling a Checkerboard. I wanted to get the kids to play the game and I didn’t have any checkers in the classroom, so I decided to program the game in Processing. Thankfully the programming went smoothly, and I finished it in time to have the Pre-Calculus class try to beat the game (it’s the day before winter break, and we just finished sequences and series). Fantastic timing.


  • Goal: remove all checkers from the green prison.
  • If you click on a checker, and there is space to the right and above, then that checker will disappear, and two clones will appear to the right and above.
  • Theoretically this game board extends to infinity to the right and above.

The game is hosted by or hosted by It should work in any web browser, including smartphones. If you’d like to increase the checkerboard size, just go to the site and “tweak” the code. The size of the board is set on the first two lines.


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Why I Blog (Nowak requested post)

Fellow Empire State rep Kate Nowak requested answers to the following in her post: Tell Me Why You Blog.

1. What hooked you on reading the blogs? Was it a particular post or person? Was it an initiative by the nice MTBoS folks? A colleague in your building got you into it? Desperation?

I got hooked on reading math blogs because I was interested in becoming a better teacher and I wasn’t finding resources in other places to satisfy this desire. Math blogs put me in touch with teachers willing to try new things out and succeed, or more importantly, fail in public.

2. What keeps you coming back? What’s the biggest thing you get out of reading and/or commenting?

Confession: I don’t comment much on blogs. Maybe I use twitter as a sounding board for my opinions? Not sure why.

I keep coming back because I keep getting good stuff. The economics of this system are tough, if you people in the #mtbos stop producing good stuff, then I’m out. Thankfully, the stuff coming out has only been getting better and more interesting.

3. If you write, why do you write? What’s the biggest thing you get out of it?

Mostly I write for myself. I process things better after writing about them. This is from a guy who hates to write (or reflect). I record things on my blog first for myself; second for others. If other people find use in my blog, fantastic. But I’d still have some version of it if it were only my Mom reading it (hi Mom!).
It’s great that people find use for things I’ve posted. Just this morning I woke up to find 15+ responses on twitter talking about a post that I put up 3 years ago. Soooo cool. Just awesome. And that there’s that stupid Oreo thing. That must count for something.

4. If you chose to enter a room where I was going to talk about blogging for an hour (or however long you could stand it), what would you hope to be hearing from me? MTBoS cheerleading and/or tourism? How-to’s? Stories?

Dunno. Give me personal stories. I’m no help here.

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How Harvey Mudd Transformed Its Computer Science Program — And Nearly Closed Its Gender Gap

From Tech Crunch. Must watch video.

Harvey Mudd is known as one of the most elite science, engineering and mathematics colleges in the world. But historically, its computer science department hasn’t exactly been known as a paragon of gender diversity — in 2006, only 10 percent of Harvey Mudd’s computer science majors were female.

But under Dr. Maria Klawe, the renowned computer scientist (and Microsoft board member) who joined Harvey Mudd as president in 2006, the gender ratio at Mudd’s CS department has changed dramatically. This year, fully 48 percent of the CS majors in Harvey Mudd’s junior class are female.

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TED: Adam Spencer – Monster Prime Numbers

Take 17 minutes out of your day and watch Adam Spencer talk about the largest known prime (found in January of 2013). Amazingly engaging.

They’re millions of digits long, and it takes an army of mathematicians and machines to hunt them down — what’s not to love about monster primes? Adam Spencer, comedian and lifelong math geek, shares his passion for these odd numbers, and for the mysterious magic of math.

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Monday Morning Math

Awesome cat photo from misadventures in HR.

If a cat could fill out a bubble sheet, and left parts II, III, and IV blank (assumption: cats can’t write in english) then the following is based on the 2013 June Regents scoring scale:

1 in 36,000 cats would pass the Integrated Algebra Regents (15 out of 30 multiple choice to score 30 out of 87 possible points. You’ve read that correctly, 34% correct is passing)
1 in 309,000,000 cats would pass the Geometry Regents (20 out of 28 multiple choice)
1 in 1,200,000,000,000 cats would pass the Algebra II Trigonometry Regents (23 out of 27 multiple choice)

P.S. Stat people, please double check my math. I am not strong in statistics, probably due my dislike of the subject. I used Stat Trek (get it?) to compute the binomial probabilities.

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Fermat Was Wrong? Puzzler

From Car Talk.

RAY: Here it is. Everyone, almost everyone remembers from his or her days in school the Pythagorean Theorem.

TOM: Yes.

RAY: A squared, plus B squared, equals C squared. And there are numbers like three, four and five; five, 12, 13 which satisfy that little equation. And many hundreds of years ago a French mathematician by the name of Fermat said, this only works for squares. He said, if you take A, B, and C, integers A, B, and C…

TOM: Yes.

RAY: And there are some A squared plus B squared that will equal C squared, and we believe that. We know we have verification of it. We got real numbers that work.

TOM: Right.

RAY: He said, if it isn’t squared but it’s something else like cubes or to the fourth power or to the fifth power, it doesn’t work. So, for example, there is no A cubed plus B cubed, which equals C cubed. There is no A to the fourth plus B to the fourth that equals C to the fourth.

As luck would have it, a young mathematician issues a statement that he has three numbers which prove Fermat’s theorem is incorrect. He calls a press conference. Now, he doesn’t want to divulge everything right away. He wants to dramatize, build a little bit, does he not?

TOM: Gonna give them one number.

RAY: He gives them all three numbers. He doesn’t tell the power.

TOM: Ah!

RAY: He’s going to give them A, B, and C. Here are the numbers, you ready?

A equals 91. B equals 56. C equals 121.

So, it just so happens that at this little impromptu press conference, there are all these science reporters from all the po-dunky little newspapers that are around this town. And one of the guys, one of the reporters has his 10-year-old kid with him, because this happens to be a holiday. He’s off from school. And the kid very sheepishly stands up and raises his hand, and he said, I hate to disagree with you, sir, but you’re wrong.

The question is, how did he know?

Love it.

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