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mxfh commented on Show HN: I was curious about spherical helix, ended up making this visualization   visualrambling.space/movi... · Posted by u/damarberlari
srean · 5 days ago
These used to be super important in early oceanic navigation. It is easier to maintain a constant bearing throughout the voyage. So that's the plan sailors would try to stick close to. These led to let loxodromic curves or rhumb lines.

https://en.m.wikipedia.org/wiki/Rhumb_line

Mercator maps made it easier to compute what that bearing ought to be.

https://en.m.wikipedia.org/wiki/Mercator_projection

This configuration is a mathematical gift that keeps giving. Look at it side on in a polar projection you get a logarithmic spiral. Look at it side on you get a wave packet. It's mathematics is so interesting that Erdos had to have a go at it [0]

On a meta note, today seems spherical geometry day on HN.

https://news.ycombinator.com/item?id=44956297

https://news.ycombinator.com/item?id=44939456

https://news.ycombinator.com/item?id=44938622

[0] Spiraling the Earth with C. G. J. Jacobi. Paul Erdös

https://pubs.aip.org/aapt/ajp/article-abstract/68/10/888/105...

mxfh · 4 days ago
Except the helix curve shown in OP is NOT a loxodrome or rhumb line.

It has equal spacing on the surface between lines, a loxodrome can't have that property since by definition it must cross the meridians at the same angle at all times. That means it always gets denser near the poles.

---

Start with the curve:

x = 10 · cos(π·t/2) · sin(0.02·π·t)

y = 10 · sin(π·t/2) · sin(0.02·π·t)

z = 10 · cos(0.02·π·t)

Convert to spherical coordinates (radius R=10):

λ(t) = π/2 · t (longitude)

φ(t) = π/2 - 0.02·π·t (latitude)

Compute derivative d(λ)/d(φ):

d(λ)/dt = π/2

d(φ)/dt = -0.02·π

d(λ)/d(φ) = (π/2)/(-0.02·π) = -25 (constant)

A true rhumb line must satisfy:

d(λ)/d(φ) = tan(α) · sec(φ)

which depends on latitude φ.

Since φ(t) changes, sec(φ) changes, so no fixed α can satisfy this.

Conclusion: the curve is not a rhumb line.

this is how one should look for varying intersection angles:

https://beta.dwitter.net/d/34223

mxfh commented on Streaming services are driving viewers back to piracy   theguardian.com/film/2025... · Posted by u/nemoniac
thaumasiotes · 10 days ago
You think pirating videos will raise your electric bill by $25 / month?
mxfh · 10 days ago
Storage isn't free. running a 50 Watt anything 24/7 costs like 10 Dollars a month in Europe already if you don't want to be an anti-social leacher or want the convenience of an netflix-like media server.

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mxfh commented on Streaming services are driving viewers back to piracy   theguardian.com/film/2025... · Posted by u/nemoniac
gjvc · 10 days ago
with a sample size of one, there is no obvious problem.

presumably any given household wants to watch more than just pokemon, though and this is where things become unstuck. suddenly, to satisfy the demand for the range of things people in the household want to watch they are forced to make subscriptions to multiple services, perhaps sometimes for one-offs.

scale this up, and you have a population forced to make multiple subscriptions to multiple streaming providers to satisfy their demand for content.

or people just choose a couple of them and that's that. either way it seems that there is a symbiotic relationship between the content authors and the streaming companies.

but wait, read the page carefully, multiple seasons of the same thing spread across different streamers forcing consumers to subscribe to multiple streamers .... and now we are into Phoebus cartel territory.

mxfh · 10 days ago
That's not how streaming worked, ever. You had to deal with what Netflix had to offer and that was it. These were the happy monopoly days. It was simply the lack of choice and nobody felt left out at watercooler talks.

The paradox now, is that if you're FOMO inclined you feel the need to subscribe to multiple ones at all times to satify all needs in a household. You don't have to. You can keep baseline Disney if you really have to, but everything else can be easily rotated or just cought up on for a month or three on the usual discounted offers. The social pressure was not some invention of the streaming companies.

Also pirating has a hardware and energy cost, that's not trivial and mostly subsidized by parents. On a ROI basis of adults with disposable income "buying" (aka personal licenses, ideally shareable with some other accounts what some might call a family) 4-5 movies for like 5 dollars on platforms like Apple TV each a month is actually cheaper than pirating. Streaming is not everything. And don`t kid yourself that your DVD or Bluray collection is worth something or usable in 20+ years. That's a niche hobby. Go visit a flea market. People are that lazy when it comes to couch and home entertainment stuff.

mxfh commented on Streaming services are driving viewers back to piracy   theguardian.com/film/2025... · Posted by u/nemoniac
crooked-v · 11 days ago
To really sum it all up in one place, check out the absurdity of the official guide on where to watch the Pokemon cartoon: https://www.pokemon.com/us/animation/where-to-watch-pokemon-...

And that doesn't even actually list the movies, which are even more fragmented.

mxfh · 10 days ago
What's the problem with that exactly? Legacy catalogs having some incomplete coverage? That the Pokemon Company can't make a good list if pressed? These are all not new or streaming Problems

The gist is here, that the complete first four season are on YouTube for free and the 5th is being added as we speak? (200+ episodes)

https://www.youtube.com/@OfficialPoke%CC%81monTV/playlists

There was nether the expectation with streaming that third party content doesn't rotate.

If you want a bit more persistent access you can buy them on Apple TV (Season 1-5 and 10-25)

Oh Boy, Pokemon is really not the example I would bring up here, when the aim is completeness on official channels:

https://en.wikipedia.org/wiki/Pok%C3%A9mon_episodes_removed_...

mxfh commented on Multimodal WFH setup: flight SIM, EE lab, and music studio in 60sqft/5.5M²   sdo.group/study... · Posted by u/brunohaid
evanjrowley · 13 days ago
There really is no precise name for these.

Source: A technology hoarder who has too many shelves like this full of junk.

Edit: I stand corrected by @bobson381

I have several of these under the Gorilla Rack brand name and they're sold as Industrial Shelving Units. Home Depot in the US also sells these under the Muscle Rack and Edsal brands. These shelves are good, but I caution against using them in rooms with uneven floors (i.e., basement floors) because the feet are not adjustable. The particle board shelf surfaces can also deteriorate easily in moist environments. OP's shelf is one coffee spill away from a ruined shelf. That particle board is also made with formaldehyde and water damage will release it, FYI.

I have even more Wire Rack Shelves from various brands, all mostly with interchangable parts. A major brand is Nexel. There's also a lot of good parts available through the Metro brand sold by The Container Store. I appreciate the Wire Rack Shelving for it's modularity, adjustable feet, and also the ability to use caster wheels. You can always cut your own solid shelf surface from whatever material you like. The drawback is these Wire Rack Shelves cost twice as much as the Industrial Shelving Units.

mxfh · 12 days ago
Why not some finished birch plywood for surfaces you work on? I get worried about my wrists just looking at that particle board.
mxfh commented on We'd be better off with 9-bit bytes   pavpanchekha.com/blog/9bi... · Posted by u/luu
mxfh · 18 days ago
I just consider ourselves lucky, that we're not stuck with 6- or 7-bit bytes in ASCII-land and made it to Code page 437.

https://en.wikipedia.org/wiki/Six-bit_character_code

mxfh commented on Show HN: I spent 6 years building a ridiculous wooden pixel display   benholmen.com/blog/kilopi... · Posted by u/benholmen
mxfh · 21 days ago
If you're willing to sacrifice a color just use triangles/prisms the faces could then just be virtually adjacent and still rotate independently

https://excalidraw.com/#json=driyv7dR-eODBzuh_hdrk,93QQvkYae...

mxfh · 20 days ago
I guess the patents are long expired now and don't really apply to pixels, but that concept exists already for non-pixelated images and sadly these are replaced mostly by LEDs now in the wild:

https://www.rotapanel.com/trivision-mechanism-and-prism-type...

mxfh commented on Show HN: I spent 6 years building a ridiculous wooden pixel display   benholmen.com/blog/kilopi... · Posted by u/benholmen
xpe · 21 days ago
Another idea: have the cubes point an edge straight forward (instead of a face). Then if each cube has two adjacent dark sides and two adjacent light sides, one could setup two ‘simultaneous’ images: one viewed from the left at 45° and another viewed from the right. (Each pixel would have four possibilities.)
mxfh · 21 days ago
If you're willing to sacrifice a color just use triangles/prisms the faces could then just be virtually adjacent and still rotate independently

https://excalidraw.com/#json=driyv7dR-eODBzuh_hdrk,93QQvkYae...

u/mxfh

KarmaCake day12445March 19, 2012
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