Ahh... Brings me memories. Back in the 80s I did something similar after reading Dawkin's The Blind Watchmaker and his Biomorph evolution app. I wanted to recreate it but doing something more fun. So I hacked an Atari Logo space invaders game that used genetic programming on the invaders that survived most of the hits based on their shape (some pixels worked as shields) and motion. After 5 levels the game was almost impossible to beat.
Readit Newspjbk commented on How to Draw a Space Invader muffinman.io/blog/invader... · Posted by u/abdusco
pjbk commented on Who Invented Backpropagation? people.idsia.ch/~juergen/... · Posted by u/nothrowaways
They're probably talking about Kalman Filters (1961) and LMS filters (1960).
To be fair, any multivariable regulator or filter (estimator) that has a quadratic component (LQR/LQE) will naturally yield a solution similar to backpropagation when an iterative algorithm is used to optimize its cost or error function through a differentiable tangent space.
pjbk commented on Who Invented Backpropagation? people.idsia.ch/~juergen/... · Posted by u/nothrowaways
As it is stated, I always thought it came from formulations like Euler-Lagrange procedures in mechanics used in numeric methods for differential geometry. In fact when I recreated the algorithm as an exercise it immediately reminded me of gradient descent for kinematics, with the Jacobian calculation for each layer similar to an iterative pose calculation in generalized coordinates. I never thought it was something "novel".
pjbk commented on Airbrush art of the 80s (2015) coolandcollected.com/airb... · Posted by u/Michelangelo11
> It’s unfortunate that the airbrush has been cast aside by many artists in favor of Photoshop or Illustrator.
I don't think so. I used to do a lot of airbrushing, in the 1980s. I even had one of these[0].
I don't miss them at all. They were a huge pain in the ass.
[0] https://paulbudzik.com/tools-techniques/Airbrushing/paasche-...
Things have improved. Modern water-based acrylic paints and sealers are much easier to deal with and give you similar if not better results than enamels. There are finally now some decent compact and quiet tank-less electric pump compressors. Cleaning solutions and cheap airbrushes are much better too. Some cheap airbrushes these days have improved designs and materials that make them superior to expensive 80s airbrushes. For example, I just got a Gaahleri Mobius airbrush and it is almost as good as my far more expensive Iwata airbrush, and far better than my old Paasche which cost me a fortune back then. The future looks bright!
pjbk commented on The secret code behind the CIA's Kryptos puzzle is up for sale news.artnet.com/art-world... · Posted by u/elahieh
Does it’s S shape, or the shadow it casts or any other physical representation of it have to do with the message?
Well, outside of Sanborn and his collaborators, who knows. When the puzzles were first revealed and people started trying to crack them, some of them explored out of the box approaches like the design of the sculpture, odd-shaped letters, shadows of the symbols, it's geographic position, etc. However eventually all first 3 turned out to be classic cryptographic algorithms (Vigenere for K1 and K2, transposition for K3), with the information to solve them contained within the cyphertext of the sculpture. For K4, Sanborn has hinted that this may not be the case.
pjbk commented on The secret code behind the CIA's Kryptos puzzle is up for sale news.artnet.com/art-world... · Posted by u/elahieh
I've spent a fair amount of time on K4, and my conclusion is that it's simply a poor puzzle. At this point 24 of 97 characters have been revealed, and yet there's seemingly still not enough information pointing to how the known plaintext corresponds to the ciphertext. Over the decades everything reasonable has been tried and eliminated, which means the solution is likely to be unreasonable.
Probably correct. Different from the other cyphers, the number of symbols is short, and correlating part of the plaintext that has been revealed gives poor measures for the full string length. It has been said that the other solutions are required to solve K4, so if the solution relies on something like character alignment, matrix coding or an even more convoluted permutation arrangement, this can look (or directly be) a one-time pad cypher which are arguably the most difficult to solve.
pjbk commented on Installing a mini-split AC in a Brooklyn apartment probablydance.com/2025/08... · Posted by u/ibobev
I just did an 18K BTU mini split in my garage myself with no HVAC background for around $1K and $300 in tools. For a little more capacity this guy paid 30-40x the price.
This article is a perfect example of why I moved out of NYC. Contractors there are more likely to be dishonest, less skilled and more expensive and have insane leverage over rich apartment dwellers who might own a screwdriver but basically have no ability (or permission) to do anything themselves.
Smart, productive people thus have large parts of their lives eaten up dealing with things that are trivial in a large majority of the country because of the density. I decided I’d rather spend my time pursuing my own goals not basic daily comfort.
I had to read that line three times to convince myself there was not an extra zero in that 40k figure. It's insane.
I always loved the isometric diagrams on Clive Maxfield's [1] books about electronics. Since a lot of circuits are non-planar (flip flops, semiconductor layers, FPGA architecture), adding a perspective view makes things uncluttered, and easier to understand and remember. I think it translates well to many technologies.
Now do Brian Orr's clouds.mid for Windows 95.
https://www.brianorr.com/blog/2010/01/14/windows-95-easter-e...
pjbk commented on Martin Crusius' Armchair Voyage historytoday.com/archive/... · Posted by u/Petiver