de Bruijn sequences (also known as Ouroborean rings in Professor Stewart’s Cabinet of Mathematical Curiosities, p. 44) are an interesting topic that have a surprising connection to moving across a square, and the security of most phone unlock screens. These sequences make a compact listing of all the possible values, in a repeating (cyclical) string of values.
Continue reading “de Bruijn sequence, security, and the surprising reason your phone requires pressing enter on the lock screen”SoME Math contest is back
The Summer of Math Exposition (run by 3blue1brown) contest is up and running: https://some.3b1b.co/
Continue reading “SoME Math contest is back”Belchou’s Aces – an oldie but a fun mathematical card trick!
In Mathematics Magic and Mystery by Martin Gardner, he describes a trick that was published in an earlier publication in 1939. This one is easy to set up and surprising, as you can have a friend run the whole trick with a few simple instructions, no sleight of hand! Here’s how it works:
Continue reading “Belchou’s Aces – an oldie but a fun mathematical card trick!”Computer vision and insect vision – compared
If you have been experimenting with the widely used OpenCV project, you may have found the StereoSGBM functionality that tries to find the difference between two images to find depth!
Continue reading “Computer vision and insect vision – compared”Another look at Zipf’s law, and you can chart it yourself!
In a previous post I showed some interesting facts about Zipf’s law and how many different things show a pattern of logarithmic decrease with the most popular or numerous item largely being much more so than the very rare ones – in a logarithmic pattern. Let’s look at that pattern and how you can chart it…
Continue reading “Another look at Zipf’s law, and you can chart it yourself!”What day is Pi Day?
Today is Tuesday, Pi day (3/14)! Pi day is a national holiday celebrating mathematics, pi, and yes sometimes some baked pie and Pi-zza…
As 3/14 is a Tuesday, so are April 4, May 9, June 6, July 4, August 8, September 5, October 31, November 7, and December 26th!
Last year Pi day was on a Monday, the year before, a Saturday. Back in 2000, Pi day was Tuesday… Check out the math trick that lets you find the day of the week for various dates throughout history!: Check out James Grime’s full explanation of the trick:
Continue reading “What day is Pi Day?”The Tic-Tac-Toe Magic Square trick
In Mathematics Magic and Mystery by Martin Gardner, the author presents an interesting card trick to create a magic square (where all rows and columns add to the same number), using an interesting interactive game with a participant. After playing a game of tic-tac-toe, your friends will be surprised to see they set up the cards in a 3×3 grid summing the number on the cards to 15!
Continue reading “The Tic-Tac-Toe Magic Square trick”Matt Parker’s Christmas Tree Net
If you haven’t seen Matt Parker’s Christmas Tree folding puzzle or received in on email/mail yet, you can read about it in one of his recent videos: I can confirm that it does fold in to a few different shapes!
Continue reading “Matt Parker’s Christmas Tree Net”Wordle game analysis with Python
Wordle is an interesting word game in the style of the old mastermind game. You can try it out on NYT puzzle page or other places. Check it out and try a round!
Continue reading “Wordle game analysis with Python”Knime conference coming up
Next week the KNIME fall conference will be happening, Nov 14-16. For mathematicians or anyone wanting to look at some useful AI/Machine learning tools, this should be an informative conference! I’ve seen some previous sessions with interesting demos and overviews of new features they add to this open-source tool. Virtual passes are free to the live-streamed event! If it is like past online lessons, it is likely they will also be available later from their Youtube channel page.