5 ms·

Off topic but I accidentally touched marcodiego's user profile instead of the title. Amazing Easter egg.

by akkartik 5y ago

marcodiego 5y ago
I'll take that as a compliment. Thanks!
- akkartik 5y ago
  Yes it is. It feels like cosmic coincidence because I lost my father 2 weeks ago.
  - marcodiego 5y ago
    Sorry for your loss. Lost mine when I was 17, I know the feeling. Hope the "Easter egg" brings you some comfort. A long time ago, during a night I couldn't sleep, I started thinking on the simplest way to calculate the volume of a torus without resorting to integrals. After a time I found a way to "turn it into a cylinder without changing its volume". Then went to my father's copy of "Simmons' Calculus with analytic geometry" to check my idea. How surprised was me to see that my father had had EXACTLY the same idea and left it written on the margin of the book! That moment I saw how careful he was to model my way of thinking to be so similar to his. I'll be eternally grateful for that.
    - akkartik 5y ago
      Thank you for that lovely story!
    - dmitryminkovsky 5y ago
      Thank you for sharing.
    - thaumasiotes 5y ago
      Hmm. Thinking about it as an integral of cross sections, the torus is just a cylinder with height equal to the circumference of the circle that defines the center of its tube. And I see that that is correct, at least for non-weird tori. https://en.wikipedia.org/wiki/Torus https://en.wikipedia.org/wiki/Torus goes on to say this: > [For a non-weird torus,] The volume of this solid torus and the surface area of its torus are easily computed using Pappus's centroid theorem > These formulas are the same as for a cylinder of length 2πR and radius r, obtained from cutting the tube along the plane of a small circle, and unrolling it by straightening out (rectifying) the line running around the center of the tube. > The losses in surface area and volume on the inner side of the tube exactly cancel out the gains on the outer side. Emphasis mine; that third sentence is weirding me out. Still thinking about it as an integral of cross sections, I can't see why the surface area or volume of the inner half of the torus should be different from the surface area / volume of the outer half. Are they?
- exikyut 5y ago
  I just had a look out of curiosity, and can 1000% recommend everyone go take 5 minutes. Also, I was extremely happy to see the Web Archive backed up the Picasaweb album view, *and* the larger view pages, *and* the comments, so you can actually still go see: https://web.archive.org/web/20110411035819/https://picasaweb.google.com/HandsAdrian/ShotwellConnect https://web.archive.org/web/20110411035819/https://picasaweb... Also, I discovered to my surprise that the Download links still work - in the literal, upstream, sense. You can strip off the Web Archive prefix, request the direct image links from Google, and they promptly download (because of "content-disposition: attachment"). How interesting (at the very least), lol. Thanks very much for the reference.
  - marcodiego 5y ago
    Thanks for your comment!
  - thaumasiotes 5y ago
    If anyone is curious about the comment from Iced, it says Thank you, and thanks to your father. He will be remembered forever.
- cb321 5y ago
  That is a nice story about open source to the sad but not so bitter sounding (BOO-YAH!) end. I am not a user (or even Gnome user), but FWIW, I looked and Adrian's eog_window_cmd_copy_image is still there almost 11 years later, only renamed in a minor way ("cmd" -> "action"). I am no expert on its churn, but the Eye Of Gnome project seems still quite active (last commit yesterday). That file src/eog-window.c itself has already had more commits since his patch than before it. { Not to suggest that code durability/quality is (or was) the whole point, but I thought being less "tears in rain" than it might have been took the inspirational factor up a notch and so seemed worth sharing here. }
tdsamardzhiev 5y ago
Thanks for pointing that out! Interactions like these were why I started using HN back in the day.
mersenne 5y ago
I don’t get it. Care to explain?
tda 5y ago
Previously discussed here https://news.ycombinator.com/item?id=2266924 https://news.ycombinator.com/item?id=2266924

Off topic but I accidentally touched marcodiego's user profile instead of the title. Amazing Easter egg.

marcodiego 5y ago

I'll take that as a compliment. Thanks!

akkartik 5y ago
Yes it is. It feels like cosmic coincidence because I lost my father 2 weeks ago.
- marcodiego 5y ago
  Sorry for your loss. Lost mine when I was 17, I know the feeling. Hope the "Easter egg" brings you some comfort. A long time ago, during a night I couldn't sleep, I started thinking on the simplest way to calculate the volume of a torus without resorting to integrals. After a time I found a way to "turn it into a cylinder without changing its volume". Then went to my father's copy of "Simmons' Calculus with analytic geometry" to check my idea. How surprised was me to see that my father had had EXACTLY the same idea and left it written on the margin of the book! That moment I saw how careful he was to model my way of thinking to be so similar to his. I'll be eternally grateful for that.
  - akkartik 5y ago
    Thank you for that lovely story!
  - dmitryminkovsky 5y ago
    Thank you for sharing.
  - thaumasiotes 5y ago
    Hmm. Thinking about it as an integral of cross sections, the torus is just a cylinder with height equal to the circumference of the circle that defines the center of its tube. And I see that that is correct, at least for non-weird tori. https://en.wikipedia.org/wiki/Torus https://en.wikipedia.org/wiki/Torus goes on to say this: > [For a non-weird torus,] The volume of this solid torus and the surface area of its torus are easily computed using Pappus's centroid theorem > These formulas are the same as for a cylinder of length 2πR and radius r, obtained from cutting the tube along the plane of a small circle, and unrolling it by straightening out (rectifying) the line running around the center of the tube. > The losses in surface area and volume on the inner side of the tube exactly cancel out the gains on the outer side. Emphasis mine; that third sentence is weirding me out. Still thinking about it as an integral of cross sections, I can't see why the surface area or volume of the inner half of the torus should be different from the surface area / volume of the outer half. Are they?
exikyut 5y ago
I just had a look out of curiosity, and can 1000% recommend everyone go take 5 minutes. Also, I was extremely happy to see the Web Archive backed up the Picasaweb album view, *and* the larger view pages, *and* the comments, so you can actually still go see: https://web.archive.org/web/20110411035819/https://picasaweb.google.com/HandsAdrian/ShotwellConnect https://web.archive.org/web/20110411035819/https://picasaweb... Also, I discovered to my surprise that the Download links still work - in the literal, upstream, sense. You can strip off the Web Archive prefix, request the direct image links from Google, and they promptly download (because of "content-disposition: attachment"). How interesting (at the very least), lol. Thanks very much for the reference.
- marcodiego 5y ago
  Thanks for your comment!
- thaumasiotes 5y ago
  If anyone is curious about the comment from Iced, it says Thank you, and thanks to your father. He will be remembered forever.
cb321 5y ago
That is a nice story about open source to the sad but not so bitter sounding (BOO-YAH!) end. I am not a user (or even Gnome user), but FWIW, I looked and Adrian's eog_window_cmd_copy_image is still there almost 11 years later, only renamed in a minor way ("cmd" -> "action"). I am no expert on its churn, but the Eye Of Gnome project seems still quite active (last commit yesterday). That file src/eog-window.c itself has already had more commits since his patch than before it. { Not to suggest that code durability/quality is (or was) the whole point, but I thought being less "tears in rain" than it might have been took the inspirational factor up a notch and so seemed worth sharing here. }

tdsamardzhiev 5y ago

Thanks for pointing that out! Interactions like these were why I started using HN back in the day.

mersenne 5y ago

I don’t get it. Care to explain?

tda 5y ago

Previously discussed here https://news.ycombinator.com/item?id=2266924 https://news.ycombinator.com/item?id=2266924