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”Computer efficiency numbers – useful rating or greenwashing?
In a recent newsletter, well known scientist Katherine Hayhoe mentioned a listing of the top most efficient computers – while efficiency is something to consider in your purchases, is there really a big difference in which laptop you buy and use?
Continue reading “Computer efficiency numbers – useful rating or greenwashing?”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 space heater that improves public health
Many of us may have an old, old computer around – did you know that you can use it as a small heater this winter, while potentially making a difference in public health and science?
Continue reading “The space heater that improves public health”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”I don’t always test BETAs on the production home page…
… but when I do, it’s WordPress.org? – Check out a recent announcement from Make WordPress Core:
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