Cool data embedded in the Bitcoin blockchain / Custom encoded images of unknown source Updated 2025-07-16
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Figure 1.
bitcoin.jpg
. Source.
A bitcoin logo on block 123573 (2011-05-13).
This is the very first ASCII string to show up at github.com/cirosantilli/bitcoin-inscription-indexer after only the Genesis block message.
Reconstructing it should likely be a simple matter of copy pasting the ASCII yEnc encoding present in the two transactions from tx ceb1a7fb57ef8b75ac59b56dd859d5cb3ab5c31168aa55eb3819cd5ddbd3d806 into a text file and decoding the yEnc, but after searching for 20 minutes Ciro couldn't find a working yEnc decoder on Ubuntu 21.10. How can a format be so dead, even after considerable extensive use in the Usenet??? It makes you think about life.
As mentioned by Ken, the logo is split across two transactions: ceb1a7fb57ef8b75ac59b56dd859d5cb3ab5c31168aa55eb3819cd5ddbd3d806 and 9173744691ac25f3cd94f35d4fc0e0a2b9d1ab17b4fe562acc07660552f95518.
There appears to be nothing strictly linking the two transactions, besides that they are very close by and the only ASCII strings around back in those pre-infinite-spam days, as can be seen at: github.com/cirosantilli/bitcoin-inscription-indexer/blob/master/data/out/0123.txt#L11, so you could just see both of them by eye.
Also the first one starts with:
=ybegin line=128 size=8776 name=bitcoin.jpg
and the second one ends in:
=yend size=8776 crc32=a7ac8449
so this is likely clearly part of the yEnc format for someone who knows it, and the filename bitcoin.jpg gives the file format.
They are not even in the same block:
both from 2011-05-13. Also note that they ended up being committed reverse order, since you don't have a strict order control over the final blockchain.
Figure 2.
v27sSra.jpg
.
An image of a dozen people siting at a dinner table, with each person identified by a Twitter handle that was edited in.
It contains a base 64 encoded image:
v27sSra.jpg

/9j/4AAQSkZJRgABAQEASABIAAD/2wBDACgcHiMeGSgjISMtKygwPGRBPDc3PHtYXUlkkYCZlo+A
...
TAkBaMxbbhuYXGDMyXw/MIV84IqrE//Z
...
By manually copy pasting that into a file v27sSra.base64 we can obtain the image with:
base64 -d <v27sSra.base64 >v27sSra.jpg
The exact same content appears to be present on the next input transaction 56d23a230042c094bc54bb72fc4c10a3f26750030b9927994e741d3689f5c09e on the same block.
Google reverse image search leads to freedom-to-tinker.com/2015/05/21/the-story-behind-the-picture-of-nick-szabo-with-other-bitcoin-researchers-and-developers/ The story behind the picture of Nick Szabo with other Bitcoin researchers and developers by Arvind Narayanan (2015), in which Arvind (@random_walker) who attended the meeting clearly lists all names and handles, and talks about the background of gathering of Bitcoin devs that happened in March 2014. The article also contains a higher resolution version of the image uploaded to the blockchain.
It also links to a popular Reddit thread that contains the image from May 2015: www.reddit.com/r/Bitcoin/comments/36hfu4/pic_coredevs_having_dinner_with_nick_szabo/
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Open access at the University of Oxford Updated 2025-07-16
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Things actually have gotten more and more closed, e.g. of stuff getting paywalled with time:
It appears that things got really bad starting in 2017, possibly when WebLearn was introduced. When things migrated to Canvas, they were closed by default, apparently with any mechanism to publish publicly.
Therefore, they managed to make things more closed than when teachers would just upload to good old ox.ac.uk/~name static websites!!
Ciro Santilli has also heard that some people in the Mathematical Institute of the University of Oxford opposed to moving away from their Moodle instance precisely because the new options did not support open publishing, so kudos to those people. But most teachers likely don't care and just do whatever is the best internally supported default.
Their "open" video material: podcasts.ox.ac.uk/ A somewhat small part is Creative Commons, but most proprietary. Despite the name "podcasts", they do contain video, it is just a relic.
podcasts.ox.ac.uk/open contains actual Creative Commons only it seems.
It does however appear that professors own their lecture notes, so there some hope maybe: governance.admin.ox.ac.uk/legislation/statute-xvi-property-contracts-and-trusts#collapse1383636
Video 1.
University of Oxford documentary by the British Council (1941)
Source.
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How to use an Oxford Nanopore MinION to extract DNA from river water and determine which bacteria live in it / BTLab Systems Mini Centrifuge Updated 2025-07-16
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Science (journal) Updated 2025-07-16
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Animal flight Updated 2025-07-16
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Base58 Updated 2025-07-16
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Invented for Bitcoin.
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Display device Updated 2025-07-16
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Functional Updated 2025-07-16
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A function that takes input function and outputs a real number.
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Joule Updated 2025-07-16
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How to use an Oxford Nanopore MinION to extract DNA from river water and determine which bacteria live in it / DNA extraction Updated 2025-07-16
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The first thing we had to do with the sample was to extract the DNA present in the water in a pure form for the PCR.
As you would expect, this consists of a purification procedure with several steps.
In each step we take a physical or chemical action on the sample, which splits it into two parts: the one with the DNA and the one without.
We then take the part with the DNA, and throw away the one without the DNA.
The first steps are coarser, and finer and finer splits are done as we move forward.
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Twelve Apostles Updated 2025-07-16
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Ciro Santilli's hardware / Cycling clothes temperature guide Updated 2025-07-16
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In degrees Celsius:
  • 25+
    • palm tree shade and coconut water. Seriously though, if there's some shade or earlier morning/later afternoon it's OK, but if it's on an open road at midday, be careful, and stop early if you start getting slightly dizzy, it only gets worse!
  • 18-25
  • 15-18:
  • 10-15:
    • dhb Classic Thermal Bib Tights 10 and under. TODO this is a bit too warm for the upper range, need something more intermediate
    • "dhb Lightweight Mesh Long Sleeve Base Layer"
    • Castelli Perfetto RoS Long Sleeve - Cycling jersey. TODO this is a bit too warm for the upper range, need something more intermediate
    • "Karrimor X Lite Run Black Headband"
    • "Nike academy hyperwarm gloves"
    • "Nevica Skuff". A bit too hot on upper range, but easy to take off.
  • 0-10:
    • dhb Merino Long Sleeve Base Layer
    • Castelli Perfetto RoS Long Sleeve - Cycling jersey
    • dhb Classic Thermal Bib Tights 10 and under
    • dhb Dorica MTB Shoe (2020-12)
    • "Karrimor X Lite Run Black Headband". Head a bit cold on lower range.
    • "dhb Neoprene Nylon Overshoes". Feet a bit cold on lower range.
    • "Extremities XDRY gloves". Hands a bit cold on lower range.
    • "Nevica Skuff"
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The Machiavellian Stack Overflow contributor Updated 2025-07-16
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  • always upvote questions you care about, to increase the probability that they will get answered
  • never upvote other people's answers unless you might gain from it somehow, otherwise you are just giving other high reputation users more reputation relative to you
  • only mark something to close or as a duplicate if it will bring you some advantage, because closing things creates enemies, especially if the OP has a high profile
    One example advantage is if you have already answered the question (and the duplicate as well in case of duplicates), because this will prevent competitors from adding new better answers to overtake you.
  • protect questions you've answered whenever someone with less than 10 reputation answers it with a bad answer, to prevent other good contributors from coming along and beating you
  • when you find a duplicate pool answer every question with similar answers.
    Alter each answer slightly to avoid the idiotic duplicate answer detector.
    If one of the question closes, it is not too bad, as it continues netting you to upvotes, and prevents new answers from coming in.
  • follow on Twitter/RSS someone who comments on the top features of new software releases. E.g. for Git, follow GitHub on Twitter, C++ on Reddit. Then run back to any question which has a new answer.
  • always upvote the question when you answer it:
    • the more upvotes, more likely people are to click it.
    • the OP is more likely to see your answer and feel good and upvote you
  • if a niche question only has few answers and you come with a good one, upvote the existing ones by other high profile users.
    This may lead to them upvoting or liking you.
    Even if they don't, other people will still see your answer anyway, and this will lead to people to upvoting you more just to make your great answer surpass the current ones, especially if the accepted one has less upvotes than yours. Being second is often an asset.
  • always upvote comments that favor you:
    • "I like this answer!" on your answers
    • "also look at that question" when you have answered that question
  • don't invest a lot in edits. They don't give you rep, and they can get reverted and waste your time.
    Why are you trying to help other people's answers to get rep anyways? Just make a separate answer instead! :-)
  • if you answer a question by newbie without 15 reputation, find their other questions if any and upvote them, so that the OP can upvote your answer in addition to just accepting
  • If you haven't answered a question, link to related questions you've answered on question comments, so more people will come to your answers.
    If you have answered the question, only link to other questions at the bottom of your answer, so that people won't go away before they reach your answer, and so as to strengthen your answer.
  • if a question has 50 million answers and you answer it (often due to a new feature), make a comment on the question pointing to your answer
  • if you get a downvote, always leave a comment asking why. It is not because you care about their useless opinion, but because other readers might see the comment, feel sorry for you, and upvote.
  • ask any questions under a separate anonymous accounts. Because:
    • intelligent people are born knowing, and don't ever ask any questions, so that would hurt your reputation
    • downvoting questions does not take 1 reputation away from the downvoter, and so it greatly opens the door for your opponents to downvote you without any cost.
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PBS Space Time Updated 2025-07-16
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Always a bit too much on the superficial side, but sometimes OK, 5-10 minute videos.
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Ciro Santilli's hardware / dhb Dorica MTB Shoe (2020-12) Updated 2025-07-16
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Black EUR 44, 1 smaller than normal size as recommended by website.
Bought SM-SH56 cleat to accompany.
When it arrived, it felt a bit too long, around 2cm maybe free space after toe, and when I walk and the front part touches ground, heel comes off a bit, which is annoying. But I was too lazy to give it back and take the risk of a second try, also it felt correctly tight on sides. During first test ride it felt good.
It is slightly water proof. But if it rains a lot, it will get soaking wet. And once it does get wet, it feels like it is very very hard to dry, there don't seem to be any holes underneath.
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C library Updated 2025-07-16
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Clickbait Updated 2025-07-16
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Thali Updated 2025-07-16
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Indian vegetarian thali is the best thing ever! The Southern version in particular. Also do watch a video on how to eat it.
A good place to have it abroad is Saravana Bhavan. The founder killed a dude to marry his wife, but failed and was sentenced to life prison. But he died in 2019 so we're all fine eating there now.
Figure 1. Source. This Wikipedia image of Thali is fundamentally wrong: you have to have a banana leaf on the bottom of the tray!
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Oxford mathematics Moodle Updated 2025-07-16
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Has a mixture of open access and closed access. But at least it can have open access unlike the in-house systems such as Canvas where everything is necessarily paywalled!
Sometimes things appear open but don't show any meaningful content if you are not logged in, which is annoying.
But at least it gives a clear public course list, thing that certain departments (cough Department of Physics of the University of Oxford cough).
The organization is a bit crap, when you expand e.g. C Michaelmas term it shows nothing, just a search.
The way to go is via the year year categories e.g. "Year 2022-23": courses.maths.ox.ac.uk/course/index.php?categoryid=734. Term splitting is annoying, but one can stand it.
There seems to be no way to list all versions of a single course across multiple years besides just doing a search e.g.
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Country in Oceania Updated 2025-07-16
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