E. Coli K-12 Updated 2025-07-16
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E. Coli genome starting point Updated 2025-07-16
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The conventional starting point is not at the E. Coli K-12 MG1655 origin of replication.
biocyc.org/ECOLI/NEW-IMAGE?type=EXTRAGENIC-SITE&object=G0-10506 explains:
This site is the origin of replication of the E. coli chromosome. It contains the binding sites for DnaA, which is critical for initiation of replication. Replication proceeds bidirectionally. For historical reasons, the numbering of E. coli's circular chromosome does not start at the origin of replication, but at the origin of transfer during conjugation.
If it is a bit hard to understand what they mean by "origin of transfer" though, as that term is usually associated with the origin of transfer of bacterial conjugation.
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Synchronous dynamic random-access memory Updated 2025-07-16
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Knuth reward check Updated 2025-07-16
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Yet another Updated 2025-07-16
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The mandatory xkcd: xkcd 927: Standards.
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It is hard for complex organisms to evolve because longer DNA means longer replication time Updated 2025-07-16
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Because DNA replication is a key limiting factor of bacterial replication time, such organisms are therefore strongly incentivized to have very minimal DNAs.
Power, Sex, Suicide by Nick Lane (2006) 7 "Why bacteria are simple" page 169 puts this nicely:
Bacteria replicate at colossal speed. [...] In two days, the mass of exponentially doubling E. coli would be 2664 times larger than the mass of the Earth.
Luckily this does not happen, and the reason is that bacteria are normally half starved. They swiftly consume all available food, whereupon their growth is limited once again by the lack of nutrients. Most bacteria spend most of their lives in stasis, waiting for a meal. Nonetheless, the speed at which bacteria do mobilize themselves to replicate upon feeding illustrates the overwhelming strength of the selection pressures at work.
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Terminal deoxynucleotidyl transferase Updated 2025-07-16
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Magnetoresistive disk head Updated 2025-07-16
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N-V center quantum computer Updated 2025-07-16
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Nitrogen-vacancy center Updated 2025-07-16
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All indefinite orthogonal groups of matrices of equal metric signature are isomorphic Updated 2025-07-16
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First we can observe that the exact matrices are different. For example, taking the standard matrix of :
(1)
and:
(2)
both have the same metric signature. However, we notice that a rotation of 90 degrees, which preserves the first form, does not preserve the second one! E.g. consider the vector , then . But after a rotation of 90 degrees, it becomes , and now ! Therefore, we have to search for an isomorphism between the two sets of matrices.
For example, consider the orthogonal group, which can be defined as shown at the orthogonal group is the group of all matrices that preserve the dot product can be defined as:
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Calendar Updated 2025-07-16
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ecash Updated 2025-07-16
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English as a universal language by Dan Dascalescu (2008) Updated 2025-07-16
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Global Interpreter Lock Updated 2025-09-09
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Invariant vs covariant Updated 2025-07-16
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Some sources distinguish "invariant" from "covariant" such that under some transformation (typically Lie group):
  • invariant: the value of does not change if we transform
  • covariant: the form of the equation does not change if we transform .
TODO examples.
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Cool data embedded in the Bitcoin blockchain / HHTT Updated 2025-07-16
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The Horrible Horrendous Terrible Tremendous Mining Pool inscribed a few cute Coinbase messages during their operation in 2012-2013.
Many of their messages also mention SockThing, which was part of their mining infrastructure:
Starting from their very first ASCII transaction on block 197602 (2012-09-07), there is what seems to be a poem spread across several transactions. Some of the lines are repeated, presumably because they didn't update the current line to a new line and so mined the same thing multiple times:
I am a pretty princess
covered in mud and blood
water with stuff in it
like everything else that wiggles or jiggles
screaming might not be your waY
see no reason to operate otherwise since
came into the world naked, wet and screaming
but silence will never be mine
until I am dead
but the smell will also give that away
gather all my things
load them in a big boat
airlift that to Kansas
and light it on fire
drop it from 7,000 feet
then railgun my corpse straight down
The sentences are not very coherent together, perhaps this is because lines were chosen by different miners one at a time.
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Cool data embedded in the Bitcoin blockchain / Prayer wars Updated 2025-07-16
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Figure 1.
Saint Eligius by Petrus Christus
. Source. Off-chain image for illustration. Eligius pool is named after Saint Eligius, patron of goldsmiths and miners[ref]
These are some of the earliest inscriptions in the blockchain, and therefore extremelly visible.
Although the prayer verses appear contiguous in ASCII dumps, Eligius was not actually mining every block: it is just that in those early days, miners still hadn't started adding advertisement messages to every block, so only Eligius shows up and appears contiguous.
At some point, opponents noticed these messages, and started adding atheist mockery graffiti replies, which appear interspersed in ASCII dumps with the prayer.
The first prayer is the Latin version of the Divine Praises, a Catholic prayer composed in 1797 in Italian by Luigi Felici for the purpose of making reparation after saying or hearing sacrilege or blasphemy. Luke claims he was referring to anything in particular that came prior in the blockchain: twitter.com/LukeDashjr/status/1749182637569122434. There arent many earlier inscriptions at all to refer to in any case! The prayer and correspondong interrupts (in transaction outputs, not by other miners) ordered by block are:
  • 139690 (2011-08-05) prayer: "Eligius/Benedictus Deus. Benedictum Nomen Sanctum eius."
  • 139717 prayer: "Eligius/Benedictus Deus. Benedictum Nomen Sanctum eius.'
  • 139758 interruption: ***************************************************. This is not a Coinbase message: www.blockchain.com/explorer/transactions/btc/23befff6eea3dded0e34574af65c266c9398e7d7d9d07022bf1cd526c5cdbc94. This Bitcoin input script appears to spend a standard P2PKH output, but it first adds an extra value to the stack which contains the ***.
  • 139792 prayer: "Benedictus Iesus Christus, verus Deus et verus homo.'
  • 139831 prayer: "Benedictum Nomen Iesu.'
  • 139838 (2011-08-06) interruption: "I LIKE TURTLES" (tx 78eb16507b3d3df615e3b474e853db4667f4b11954ec6d918b1ded0fca7ad25a)
  • 138898 prayer: "Benedictum Cor eius sacratissimum."
  • 139904 prayer: "Benedictus Sanguis eius pretiosissimus."
  • 139921 prayer: "Benedictus Iesus in sanctissimo altaris Sacramento."
  • 139942 prayer: "Benedictus Sanctus Spiritus, Paraclitus."
  • 139954 interrupion: "aC-C-C-COMBO BREAKER" (tx 138c024a76df99ecafd2236d5429cf574b7778a3c6508bd83f116c832f3c6980)
  • 139960 prayer: "Benedictus Sanctus Spiritus, Paraclitus."
  • 139977 prayer: "Benedicta excelsa Mater Dei, Maria sanctissima."
  • 139990 (2011-08-06) prayer: "Benedicta sancta eius et immaculata Conceptio."
Then comes:
and various others + output message interruptions.
Then at last come the first miner message interruptions. Luke explained on Twitter[ref] that they were also made by Eligius pool, as there was a system in which contributors besides Luke could submit their own strings:
followed by more prayers and interruptions such as tx ec92d245822fa1ff862f3314b9102f36fe1eb8bc055865674c75323540aedef6:
FFS Luke-Jr leave the blockchain alone!
Oh, and God isn't real
The last Luke prayer appears to be on block 143822 (2011-09-03)
... the Lord of the harvest, that he send forth labourers into his harvest.
Then there is a bit of radio silence, until finally Slush Pool started self advertising for the first time on block 163970 (2012-01-26):
/P2SH/BIP16/slush/R,
They had been mining for a long time by then (December 2010 according to en.bitcoin.it/wiki/Slush_Pool), but this is when they decided to add a human readable ASCII message as well.
From then on, miner messages would be forever polluted with ads, and Luke's multi-miner message feat would never again be reproduced.
The non-obvious interruptions are all well known memes/anime references:
Bibliography:
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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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Cool data embedded in the Bitcoin blockchain / AtomSea & EMBII Updated 2026-04-05
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"AtomSea & EMBII" refers to an upload system for various media types includeing text, images, HTML pages and audio.
The official name used by its creators for the protocol is P2FK (Pay To Future Key).
The name "AtomSea & EMBII" is a reference to the online handles of its creators. That string appears to be added as padding in the protocol and is therefore visible repeatebly in the blockchain, though it is sometimes cut up a bit. The following online profiles of the creators feel authentic:
Tried saying hi to them at: twitter.com/cirosantilli/status/1382080760774033415 and they replied: twitter.com/AllenVandever/status/1563964396656812034
The feature-set of their protocol is impressive:
Basically they've created a fully descentralized Bitcoin-based social media. Their system is basically a sligly more clunky superset of Ordinal ruleset inscriptions, just way older and way less known for whatever reason.
Each P2FK inscription is done over P2FKH payloads. Each inscription a toplevel transaction which links to other transactions. All the linked transactions together make up the payload. The most common payload type is a text plus image, as is the case of Nelson-Mandela.jpg, which can be seen at bitfossil.org/root/78f0e6de0ce007f4dd4a09085e649d7e354f70bc7da06d697b167f353f115b8e/ where 78f0e6de0ce007f4dd4a09085e649d7e354f70bc7da06d697b167f353f115b8e is the toplevel transaction ID: www.blockchain.com/btc/tx/78f0e6de0ce007f4dd4a09085e649d7e354f70bc7da06d697b167f353f115b8e See Section "Nelson-Mandela.jpg" for a detailed reverse engineering of the format, and Section "AtomSea & EMBII data format" for a summary of it.
The system shows the messages and the images on a single page: bitfossil.org/root/4cbb32cd27b5b5edc12d3559bdffc1355ac2a210463d5cfaadc7ce9b06675b2b/index.htm It is basically a blockchain-based Twitter.
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