Or do I mean Logic Square? Because it works either way. The Logic Square (or Square Logic) in question is a logic game created by Charles Lutwidge Dodgson (1832-1898) and introduced in his 1896 book Symbolic Logic Part I (a second part was published posthumously).
Dodgson was a capable mathematician, but most probably know him by his penname, Lewis Carroll, under which he wrote poetic fantasy fiction about a girl who goes on wild adventures.
But this is about his logic game. It’s like a square Venn diagram with game pieces.
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5 Comments | tags: boolean logic, four-square, Lewis Carroll, logic, logic games, Venn diagram | posted in Basics, Math
I was going through old files I’ve kept around for too long and found a collection of images a friend sent me years ago. We met in college and have been friends since. She ended up working in advertising, plus her husband had a graphic design business, so she was pretty attuned to and interested in the world of visual arts and advertising.
And she had a great sense of humor. The images in the post are all (as far as we know) actual ads from a bygone era. An era that had its features, but which I think most are pretty glad is bygone.
Caveat lector: In my case, these led to tears of laughter, but for some they could lead to gnashing of the teeth. Try to see it as a sign of how much we’ve grown.
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13 Comments | tags: funny images, humor, laugh | posted in From My Collection, Life, Society
Most of the remnants of “the gang” went to see Peter Gabriel at the Xcel Energy Center in St. Paul last night. As they say, a (very) good time was had by all. It was the sort of enjoyable (and energetic) night that keeps you smiling to yourself for days. I do so love live music.
And, wow, does Gabriel (at 73!) put on a show worth seeing and hearing. Some rockers haven’t aged well, but Gabriel continues to find new visual and musical expression. Last night was as memorable as any of his previous shows.
I don’t have a lot to say — still basking in the afterglow — but I do have pictures.
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19 Comments | tags: Peter Gabriel | posted in Life, Music
Whatever you think about Tom Cruise the person, it’s hard to dispute that Tom Cruise the actor has turned out a lot of very worthwhile films. It’s hard to find many duds in his filmography but easy to spot noteworthy titles. Ever since Risky Business (1983) and Top Gun (1986), Tom Cruise has starred in movies so memorable that they became part of our cultural lingo.
More importantly for this Sci-Fi Saturday post, Tom Cruise has appeared in a perhaps surprising number of science fiction movies. Even more importantly, nearly all of them are good science fiction movies. Some of them are even really good.
Unfortunately, one of his rare duds is among them.
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11 Comments | tags: Edge of Tomorrow, Humphrey Bogart, Minority Report, science fiction, science fiction movies, SF, SF Movies, Tom Cruise | posted in Movies, Sci-Fi Saturday
It occurred to me that, to some extent, I’d like my most of my blog posts to be like these Friday Notes posts: extemporaneous ramblings and the setting free of any notes recently captured. And some old stories (and maybe a few pictures).
It’s not that I want to stop ‘splaining stuff, my inner teacher is strong. (Is it man-splaining if you’re a teacher?) It’s been one of my things since grade school. Spead knowledge!
But the rambling sure is easy. And fun!
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5 Comments | tags: autumnal equinox, dragons, equinox, lava, wasps | posted in Friday Notes
It’s been a while, but the two previous posts in this series (this one and this one) explored the mechanism behind partial differential equations that equate the time derivative (the rate of change), with the second spatial derivative (the field curvature). The result pulls exceptions to the average back to the average in proportion to how exceptional they are.
Such equalities appear in many classical physics equations where they have clear physical meaning. Heat diffusion (explored in the previous posts) is a good example.
In quantum mechanics, they also appear in the Schrödinger Equation.
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6 Comments | tags: QM101, quantum mechanics, Schrödinger Equation, wave-function | posted in Math, Physics
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Stay resistive, my friends! Go forth and spread beauty and light.
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2 Comments | tags: hot resistor, sun sign | posted in Life
Another (very) late edition and in the same week [see previous post]. In this case, it’s because I hadn’t planned a Friday Notes post for today, but I’ve gotten so indolent lately that I’m falling out of the habit of blogging. (Or, the eternal question, have I perhaps gotten weary of it?)
But, as polite people say, “Stuff happens.” And because it does, I have enough perishable notes that I may have to put out two Notes editions this month.
Assuming I can get back in the blogging habit.
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2 Comments | tags: blogging, Stephen R. Donaldson, weather | posted in Friday Notes
A late edition Mystery Monday post because I’ve been distracted by various and sundry. I’ve meant this for more than one previous Monday. Not gonna miss another.
Having pretty thoroughly explored the British Queens of Crime as well as (the American) Ellery Queen, I’ve turned to new pastures: the Butch Karp / Marlene Ciampi stories by Robert K. Tanenbaum and the Matthew Scudder stories by Lawrence Block. And French author Maurice Lablanc!
Plus, I’m disgruntled by Dark Winds, an AMC TV series that (too loosely, IMO) adapts two novels from the Navajo Tribal Police series by Tony Hillerman.
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12 Comments | tags: adaptations, Anne Hillerman, Arsène Lupin, Jim Chee, Joe Leaphorn, Lawrence Block, Lupin (TV series), Lupin the Third, Matthew Scudder, Tony Hillerman | posted in Books, Mystery Monday
Long ago (in the first year of this blog), I posted Sideband #34: The North Star, which was about how sighting on the North Star (Polaris) gives you your latitude. Simply put, the elevation of the star is your latitude. My Twin Cities are at 45° north, so Polaris is 45° above my northern horizon. Simple!
In this Sideband, I’ll explain how you can use your wristwatch as a compass. Assuming your watch is an analog one with hands. And assuming you can see the Sun (so this doesn’t work at night).
But, unlike North Star navigation, this one does work in the southern hemisphere.
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9 Comments | tags: celestial navigation, Dick Francis, south, Sun, wearing a watch | posted in Basics, Sideband
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