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Yes, we've been encouraging recreational use of hexaflexagons and even hexaflexagon parties to happen on Oct. 21, but be sure to flex responsibly.This is my third hexaflexagon video this month. The first two are also awesome.Hexaflexagons: http://youtu.be/VIVIegSt81k Hexaflexagons 2: http://youtu.be/paQ10POrZh8To learn more about flexagons, Martin Gardner, or hosting a hexaflexagon party, go here: http://www.puzzles.com/hexaflexagonI stole the \"hexaflexadyslexia\" joke from @matthetube: https://twitter.com/matthetube/status/255446894128529408I'm @vihartvihart. 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This is a song about Tau! Other Tau things you should see:Pi is (still) Wrong: http://youtu.be/jG7vhMMXagQ What Tau Sounds Like: http://youtu.be/3174T-3-59QThe Tau Manifesto: http://tauday.com/", "id": "877506826", "description_html": "Happy Tau Day! This is a song about Tau! Other Tau things you should see:Pi is (still) Wrong: http://youtu.be/jG7vhMMXagQ What Tau Sounds Like: http://youtu.be/3174T-3-59QThe Tau Manifesto: http://tauday.com/", "title": "A song about a circle constant", "progress_key": "v877506826", "edit_slug": "edit/v/877506826", "author_names": ["Vi Hart"], "deleted_mod_time": "2013-07-13T00:03:07Z", "description": "Happy Tau Day! This is a song about Tau! Other Tau things you should see:Pi is (still) Wrong: http://youtu.be/jG7vhMMXagQ What Tau Sounds Like: http://youtu.be/3174T-3-59QThe Tau Manifesto: http://tauday.com/", "extra_properties": null, "node_slug": "v/a-song-about-a-circle-constant", "deleted": false, "backup_timestamp": "2013-09-23T10:33:41Z", "date_added": "2012-06-28T17:41:30Z", "download_urls": {"mp4": "http://s3.amazonaws.com/KA-youtube-converted/FtxmFlMLYRI.mp4/FtxmFlMLYRI.mp4", "png": "http://s3.amazonaws.com/KA-youtube-converted/FtxmFlMLYRI.mp4/FtxmFlMLYRI.png", "m3u8": "http://s3.amazonaws.com/KA-youtube-converted/FtxmFlMLYRI.m3u8/FtxmFlMLYRI.m3u8"}, "translated_youtube_lang": "en", "kind": "Video", "url": "http://www.youtube.com/watch?v=FtxmFlMLYRI&feature=youtube_gdata_player", "ka_user_license": "cc-by-nc-sa", "global_id": "v877506826", "sha": "2c9ebaa1f712941b941d1b9eebe5e90be56c5011", "translated_description": "Happy Tau Day! This is a song about Tau! Other Tau things you should see:Pi is (still) Wrong: http://youtu.be/jG7vhMMXagQ What Tau Sounds Like: http://youtu.be/3174T-3-59QThe Tau Manifesto: http://tauday.com/", "image_url": "https://img.youtube.com/vi/FtxmFlMLYRI/hqdefault.jpg", "youtube_id": "FtxmFlMLYRI", "content_kind": "Video", "readable_id": "a-song-about-a-circle-constant"}, {"translated_youtube_id": "jG7vhMMXagQ", "relative_url": "/video/pi-is--still--wrong", "has_questions": false, "keywords": "pi, tau, pie, pi day, trigonometry, trig, math, mathematics, Magritte, charlie sheen", "ka_url": "http://www.khanacademy.org/video/pi-is--still--wrong", "duration": 317, "translated_title": "Pi is (still) wrong.", "translated_description_html": "Please excuse the simple math and spelling errors. You shouldn't believe anything I say without double-checking even at the best of times.\n\nGo here: http://tauday.com/\nand here: http://www.math.utah.edu/~palais/pi.html\n\nMe: http://vihart.com", "id": "538086220", "description_html": "Please excuse the simple math and spelling errors. You shouldn't believe anything I say without double-checking even at the best of times.\n\nGo here: http://tauday.com/\nand here: http://www.math.utah.edu/~palais/pi.html\n\nMe: http://vihart.com", "title": "Pi is (still) wrong.", "progress_key": "v538086220", "edit_slug": "edit/v/538086220", "author_names": ["Sal Khan"], "deleted_mod_time": "2013-07-13T00:03:07Z", "description": "Please excuse the simple math and spelling errors. You shouldn't believe anything I say without double-checking even at the best of times.\n\nGo here: http://tauday.com/\nand here: http://www.math.utah.edu/~palais/pi.html\n\nMe: http://vihart.com", "extra_properties": {"original_url": ""}, "node_slug": "v/pi-is--still--wrong", "deleted": false, "backup_timestamp": "2013-09-23T10:33:40Z", "date_added": "2012-01-31T01:36:23Z", "download_urls": {"mp4": "http://s3.amazonaws.com/KA-youtube-converted/jG7vhMMXagQ.mp4/jG7vhMMXagQ.mp4", "png": "http://s3.amazonaws.com/KA-youtube-converted/jG7vhMMXagQ.mp4/jG7vhMMXagQ.png", "m3u8": "http://s3.amazonaws.com/KA-youtube-converted/jG7vhMMXagQ.m3u8/jG7vhMMXagQ.m3u8"}, "translated_youtube_lang": "en", "kind": "Video", "url": "http://www.youtube.com/watch?v=jG7vhMMXagQ&feature=youtube_gdata_player", "ka_user_license": "cc-by-nc-sa", "global_id": "v538086220", "sha": "cd85548e85b8ae6d7be6b27b54446df7226143b5", "translated_description": "Please excuse the simple math and spelling errors. You shouldn't believe anything I say without double-checking even at the best of times.\n\nGo here: http://tauday.com/\nand here: http://www.math.utah.edu/~palais/pi.html\n\nMe: http://vihart.com", "image_url": "https://img.youtube.com/vi/jG7vhMMXagQ/hqdefault.jpg", "youtube_id": "jG7vhMMXagQ", "content_kind": "Video", "readable_id": "pi-is--still--wrong"}, {"translated_youtube_id": "D2xYjiL8yyE", "relative_url": "/video/rhapsody-on-the-proof-of-pi---4", "has_questions": false, "keywords": "mathematics, graphs, infinity, fractals, polygons, doodling, vi hart", "ka_url": "http://www.khanacademy.org/video/rhapsody-on-the-proof-of-pi---4", "duration": 356, "translated_title": "Rhapsody on the proof of pi = 4", "translated_description_html": "Correction: when I mark where pi is on the graph, I meant pi/2!\nNote: If this video were supposed to be teaching you, I'd probably have to make it boring and say that in one sense of limits, spoiler alert, you actually do approach a circle and a line, solving the apparent paradox by saying that the invariant of length does not hold over infinity. Luckily I am an artist, and this is a Rhapsody, and instead of \"learning,\" you get to actually think, if you like.", "id": "756416991", "description_html": "Correction: when I mark where pi is on the graph, I meant pi/2!\nNote: If this video were supposed to be teaching you, I'd probably have to make it boring and say that in one sense of limits, spoiler alert, you actually do approach a circle and a line, solving the apparent paradox by saying that the invariant of length does not hold over infinity. Luckily I am an artist, and this is a Rhapsody, and instead of \"learning,\" you get to actually think, if you like.", "title": "Rhapsody on the proof of pi = 4", "progress_key": "v756416991", "edit_slug": "edit/v/756416991", "author_names": ["Vi Hart"], "deleted_mod_time": "2013-07-13T00:03:08Z", "description": "Correction: when I mark where pi is on the graph, I meant pi/2!\nNote: If this video were supposed to be teaching you, I'd probably have to make it boring and say that in one sense of limits, spoiler alert, you actually do approach a circle and a line, solving the apparent paradox by saying that the invariant of length does not hold over infinity. Luckily I am an artist, and this is a Rhapsody, and instead of \"learning,\" you get to actually think, if you like.", "extra_properties": null, "node_slug": "v/rhapsody-on-the-proof-of-pi---4", "deleted": false, "backup_timestamp": "2013-09-22T10:35:41Z", "date_added": "2012-05-01T18:27:17Z", "download_urls": {"mp4": "http://s3.amazonaws.com/KA-youtube-converted/D2xYjiL8yyE.mp4/D2xYjiL8yyE.mp4", "png": "http://s3.amazonaws.com/KA-youtube-converted/D2xYjiL8yyE.mp4/D2xYjiL8yyE.png", "m3u8": "http://s3.amazonaws.com/KA-youtube-converted/D2xYjiL8yyE.m3u8/D2xYjiL8yyE.m3u8"}, "translated_youtube_lang": "en", "kind": "Video", "url": "http://www.youtube.com/watch?v=D2xYjiL8yyE&feature=youtube_gdata_player", "ka_user_license": "cc-by-nc-sa", "global_id": "v756416991", "sha": "0c43eadb3d3457152d55bcf14da3fe68249b3c0e", "translated_description": "Correction: when I mark where pi is on the graph, I meant pi/2!\nNote: If this video were supposed to be teaching you, I'd probably have to make it boring and say that in one sense of limits, spoiler alert, you actually do approach a circle and a line, solving the apparent paradox by saying that the invariant of length does not hold over infinity. Luckily I am an artist, and this is a Rhapsody, and instead of \"learning,\" you get to actually think, if you like.", "image_url": "https://img.youtube.com/vi/D2xYjiL8yyE/hqdefault.jpg", "youtube_id": "D2xYjiL8yyE", "content_kind": "Video", "readable_id": "rhapsody-on-the-proof-of-pi---4"}, {"translated_youtube_id": "uXoh6vi6J5U", "relative_url": "/video/are-shakespeare-s-plays-encoded-within-pi", "has_questions": false, "keywords": "pi, pi day, shakespeare, sonnets, mathematics, normal numbers", "ka_url": "http://www.khanacademy.org/video/are-shakespeare-s-plays-encoded-within-pi", "duration": 226, "translated_title": "Are Shakespeare's plays encoded within pi?", "translated_description_html": "Happy Pi Day! Also see: Pi is (still) Wrong: http://youtu.be/jG7vhMMXagQ\nPi in Binary Hand Dance: http://youtu.be/OCYZTg3jahU\nSpecial thanks to Toby (or not Toby) for playing Dog Hamlet.\n\nThis cool website lets you search the first 200,000,000 digits of Pi. See if your phone number or encoded name is in there! http://www.angio.net/pi/piquery\n\nSeven Sonnets:\n\nAre Shakespeare's plays encoded within Pi? \nThe truth is: we don't know, but we suspect\nThey're somewhere in those digits. And now I\nWill show why we don't know if we're correct.\n\nYou see, we think the digits do behave\nAs if they were a random sequence, and\nSo many mathematicians tried to brave\nThis question, but we still don't understand.\n\nPi isn't random: each digit must be\nExactly what the definition states.\nIt's pseudo-random, far as we can see,\nBut it's the subject of intense debates.\n\nNow I'll explain, with this parameter:\nIt's all in iambic pentameter.\n\nYou may have heard of this scenario:\nA thousand monkeys type at keyboards 'till\nThey write the works of Shakespeare. Even though,\nIn one life it's a task they can't fulfill.\n\nIf you allow their kids to carry on,\nAll through the generations working hard,\nThey will evolve before they come upon\nA single sonnet written by the Bard.\n\nBut still, the theory's sound! And it is true\nThat with a random and infinite set\nOf letters, that eventu-ally you\nWill find whatever words you want to get.\n\nHowever, on this thing you can depend:\nBefore you do, the universe will end.\n\n\nPi is a number, and that's why I can\nCompletely guarantee no part will be\n9-1-3-7-5-2-2-8-ten\n4-7-9-H-A-M-L-E-T.\n\nYou'd have to make up something, like a code\nWhere zero-one is A, Oh-three is C,\nOr you could also choose some other mode,\nOh-2 could be \"to be or not to be.\"\n\nBut let's go with this system, where a Y\nIs 2-5, O's one five, and R's eighteen,\nAnd next comes zero 9 which is an I,\nOh-three, eleven. Yorick's name is seen!\n\nDoes Pi say anything? How does it go?\n1-4-1-5. I guess the answer's \"no.\"\n\n\nIf you desire to search Pi for a thing\nLike Hamlet, as if you'd 'discover' it,\nWithout a copy used for referencing,\nYou wouldn't know if you'd recovered it.\n\nIn fact, it's almost certain, so beware:\nBefore you get to Hamlet, if you slog\nThrough all the digits, you'll find versions where\nThere's just one thing changed: Hamlet is a dog.\n\nDog Hamlet is so awesome and he goes\nOn infinitely many adventures.\nIn this infinite space everyone knows\nDog Hamlet's king. Sometimes he has dentures.\n\nUnless Pi isn't normal. I'll admit:\nPi might not have a single Dog Hamlet.\n\n\nA normal number is a number where,\nIf you take any pattern of length Z\nYou'll definitely find the pattern there,\nAnd others that length, with' same frequency.\n\nLength 1 would just be every digit, so\nAll digits happen infinity times.\nAnd all two-digit numbers also go\nIn there somewhere. If you list all the primes,\n\nYou get the Copeland-Erdos constant, which\nIs one of few known normal numbers. Or\nTake every number in order and stitch\nThem all together. And we know there's more.\n\nMost numbers must be of the normal kind,\nBut somehow they are hard for us to find.\n\n\nWe think that Pi is normal. Also e\nAnd square root 2 and other stuff like that.\nWe don't know how to prove that they must be,\nThat Pi contains Macbeth where he's a cat.\n\nIf you've got every combination of\nDigits of every length, that will include\nA Romeo and Juliet in love\nWho meet in time and live and end the feud.\n\nAnd since the strings of numbers must occur\nWith equal frequency to other strings\nOf the same length, it don't matter whether\nYou choose this code or other permutings.\n\nPerhaps somewhere Dog Hamlet and Catbeth\nAre chillin', bustin' ghosts, avoiding death.\n\n\nThere's simple open problems about pi,\nLike whether every digit, oh through nine,\nKeeps happening. We can't figure out why\n6 shouldn't stop appearing, down the line.\n\nIt seems ridiculous, to think that 2\nOccurs finitely many times. I fear,\nThat without proof, we can't say it's not true.\nAlas, poor Yorick may never appear.\n\nBut the exciting thing is that I think\nThese problems will be solved before too long.\nAnd then this video will really stink\nBecause all this not-knowing will be wrong.\n\nDon't worry; I look forward to its fall.\n'Till then, a happy Pi Day to you all.", "id": "656321710", "description_html": "Happy Pi Day! Also see: Pi is (still) Wrong: http://youtu.be/jG7vhMMXagQ\nPi in Binary Hand Dance: http://youtu.be/OCYZTg3jahU\nSpecial thanks to Toby (or not Toby) for playing Dog Hamlet.\n\nThis cool website lets you search the first 200,000,000 digits of Pi. See if your phone number or encoded name is in there! http://www.angio.net/pi/piquery\n\nSeven Sonnets:\n\nAre Shakespeare's plays encoded within Pi? \nThe truth is: we don't know, but we suspect\nThey're somewhere in those digits. And now I\nWill show why we don't know if we're correct.\n\nYou see, we think the digits do behave\nAs if they were a random sequence, and\nSo many mathematicians tried to brave\nThis question, but we still don't understand.\n\nPi isn't random: each digit must be\nExactly what the definition states.\nIt's pseudo-random, far as we can see,\nBut it's the subject of intense debates.\n\nNow I'll explain, with this parameter:\nIt's all in iambic pentameter.\n\nYou may have heard of this scenario:\nA thousand monkeys type at keyboards 'till\nThey write the works of Shakespeare. Even though,\nIn one life it's a task they can't fulfill.\n\nIf you allow their kids to carry on,\nAll through the generations working hard,\nThey will evolve before they come upon\nA single sonnet written by the Bard.\n\nBut still, the theory's sound! And it is true\nThat with a random and infinite set\nOf letters, that eventu-ally you\nWill find whatever words you want to get.\n\nHowever, on this thing you can depend:\nBefore you do, the universe will end.\n\n\nPi is a number, and that's why I can\nCompletely guarantee no part will be\n9-1-3-7-5-2-2-8-ten\n4-7-9-H-A-M-L-E-T.\n\nYou'd have to make up something, like a code\nWhere zero-one is A, Oh-three is C,\nOr you could also choose some other mode,\nOh-2 could be \"to be or not to be.\"\n\nBut let's go with this system, where a Y\nIs 2-5, O's one five, and R's eighteen,\nAnd next comes zero 9 which is an I,\nOh-three, eleven. Yorick's name is seen!\n\nDoes Pi say anything? How does it go?\n1-4-1-5. I guess the answer's \"no.\"\n\n\nIf you desire to search Pi for a thing\nLike Hamlet, as if you'd 'discover' it,\nWithout a copy used for referencing,\nYou wouldn't know if you'd recovered it.\n\nIn fact, it's almost certain, so beware:\nBefore you get to Hamlet, if you slog\nThrough all the digits, you'll find versions where\nThere's just one thing changed: Hamlet is a dog.\n\nDog Hamlet is so awesome and he goes\nOn infinitely many adventures.\nIn this infinite space everyone knows\nDog Hamlet's king. Sometimes he has dentures.\n\nUnless Pi isn't normal. I'll admit:\nPi might not have a single Dog Hamlet.\n\n\nA normal number is a number where,\nIf you take any pattern of length Z\nYou'll definitely find the pattern there,\nAnd others that length, with' same frequency.\n\nLength 1 would just be every digit, so\nAll digits happen infinity times.\nAnd all two-digit numbers also go\nIn there somewhere. If you list all the primes,\n\nYou get the Copeland-Erdos constant, which\nIs one of few known normal numbers. Or\nTake every number in order and stitch\nThem all together. And we know there's more.\n\nMost numbers must be of the normal kind,\nBut somehow they are hard for us to find.\n\n\nWe think that Pi is normal. Also e\nAnd square root 2 and other stuff like that.\nWe don't know how to prove that they must be,\nThat Pi contains Macbeth where he's a cat.\n\nIf you've got every combination of\nDigits of every length, that will include\nA Romeo and Juliet in love\nWho meet in time and live and end the feud.\n\nAnd since the strings of numbers must occur\nWith equal frequency to other strings\nOf the same length, it don't matter whether\nYou choose this code or other permutings.\n\nPerhaps somewhere Dog Hamlet and Catbeth\nAre chillin', bustin' ghosts, avoiding death.\n\n\nThere's simple open problems about pi,\nLike whether every digit, oh through nine,\nKeeps happening. We can't figure out why\n6 shouldn't stop appearing, down the line.\n\nIt seems ridiculous, to think that 2\nOccurs finitely many times. I fear,\nThat without proof, we can't say it's not true.\nAlas, poor Yorick may never appear.\n\nBut the exciting thing is that I think\nThese problems will be solved before too long.\nAnd then this video will really stink\nBecause all this not-knowing will be wrong.\n\nDon't worry; I look forward to its fall.\n'Till then, a happy Pi Day to you all.", "title": "Are Shakespeare's plays encoded within pi?", "progress_key": "v656321710", "edit_slug": "edit/v/656321710", "author_names": ["Vi Hart"], "deleted_mod_time": "2013-07-13T00:03:07Z", "description": "Happy Pi Day! Also see: Pi is (still) Wrong: http://youtu.be/jG7vhMMXagQ\nPi in Binary Hand Dance: http://youtu.be/OCYZTg3jahU\nSpecial thanks to Toby (or not Toby) for playing Dog Hamlet.\n\nThis cool website lets you search the first 200,000,000 digits of Pi. See if your phone number or encoded name is in there! http://www.angio.net/pi/piquery\n\nSeven Sonnets:\n\nAre Shakespeare's plays encoded within Pi? \nThe truth is: we don't know, but we suspect\nThey're somewhere in those digits. And now I\nWill show why we don't know if we're correct.\n\nYou see, we think the digits do behave\nAs if they were a random sequence, and\nSo many mathematicians tried to brave\nThis question, but we still don't understand.\n\nPi isn't random: each digit must be\nExactly what the definition states.\nIt's pseudo-random, far as we can see,\nBut it's the subject of intense debates.\n\nNow I'll explain, with this parameter:\nIt's all in iambic pentameter.\n\nYou may have heard of this scenario:\nA thousand monkeys type at keyboards 'till\nThey write the works of Shakespeare. Even though,\nIn one life it's a task they can't fulfill.\n\nIf you allow their kids to carry on,\nAll through the generations working hard,\nThey will evolve before they come upon\nA single sonnet written by the Bard.\n\nBut still, the theory's sound! And it is true\nThat with a random and infinite set\nOf letters, that eventu-ally you\nWill find whatever words you want to get.\n\nHowever, on this thing you can depend:\nBefore you do, the universe will end.\n\n\nPi is a number, and that's why I can\nCompletely guarantee no part will be\n9-1-3-7-5-2-2-8-ten\n4-7-9-H-A-M-L-E-T.\n\nYou'd have to make up something, like a code\nWhere zero-one is A, Oh-three is C,\nOr you could also choose some other mode,\nOh-2 could be \"to be or not to be.\"\n\nBut let's go with this system, where a Y\nIs 2-5, O's one five, and R's eighteen,\nAnd next comes zero 9 which is an I,\nOh-three, eleven. Yorick's name is seen!\n\nDoes Pi say anything? How does it go?\n1-4-1-5. I guess the answer's \"no.\"\n\n\nIf you desire to search Pi for a thing\nLike Hamlet, as if you'd 'discover' it,\nWithout a copy used for referencing,\nYou wouldn't know if you'd recovered it.\n\nIn fact, it's almost certain, so beware:\nBefore you get to Hamlet, if you slog\nThrough all the digits, you'll find versions where\nThere's just one thing changed: Hamlet is a dog.\n\nDog Hamlet is so awesome and he goes\nOn infinitely many adventures.\nIn this infinite space everyone knows\nDog Hamlet's king. Sometimes he has dentures.\n\nUnless Pi isn't normal. I'll admit:\nPi might not have a single Dog Hamlet.\n\n\nA normal number is a number where,\nIf you take any pattern of length Z\nYou'll definitely find the pattern there,\nAnd others that length, with' same frequency.\n\nLength 1 would just be every digit, so\nAll digits happen infinity times.\nAnd all two-digit numbers also go\nIn there somewhere. If you list all the primes,\n\nYou get the Copeland-Erdos constant, which\nIs one of few known normal numbers. Or\nTake every number in order and stitch\nThem all together. And we know there's more.\n\nMost numbers must be of the normal kind,\nBut somehow they are hard for us to find.\n\n\nWe think that Pi is normal. Also e\nAnd square root 2 and other stuff like that.\nWe don't know how to prove that they must be,\nThat Pi contains Macbeth where he's a cat.\n\nIf you've got every combination of\nDigits of every length, that will include\nA Romeo and Juliet in love\nWho meet in time and live and end the feud.\n\nAnd since the strings of numbers must occur\nWith equal frequency to other strings\nOf the same length, it don't matter whether\nYou choose this code or other permutings.\n\nPerhaps somewhere Dog Hamlet and Catbeth\nAre chillin', bustin' ghosts, avoiding death.\n\n\nThere's simple open problems about pi,\nLike whether every digit, oh through nine,\nKeeps happening. We can't figure out why\n6 shouldn't stop appearing, down the line.\n\nIt seems ridiculous, to think that 2\nOccurs finitely many times. I fear,\nThat without proof, we can't say it's not true.\nAlas, poor Yorick may never appear.\n\nBut the exciting thing is that I think\nThese problems will be solved before too long.\nAnd then this video will really stink\nBecause all this not-knowing will be wrong.\n\nDon't worry; I look forward to its fall.\n'Till then, a happy Pi Day to you all.", "extra_properties": null, "node_slug": "v/are-shakespeare-s-plays-encoded-within-pi", "deleted": false, "backup_timestamp": "2013-09-23T10:33:40Z", "date_added": "2012-03-14T20:23:15Z", "download_urls": {"mp4": "http://s3.amazonaws.com/KA-youtube-converted/uXoh6vi6J5U.mp4/uXoh6vi6J5U.mp4", "png": "http://s3.amazonaws.com/KA-youtube-converted/uXoh6vi6J5U.mp4/uXoh6vi6J5U.png", "m3u8": "http://s3.amazonaws.com/KA-youtube-converted/uXoh6vi6J5U.m3u8/uXoh6vi6J5U.m3u8"}, "translated_youtube_lang": "en", "kind": "Video", "url": "http://www.youtube.com/watch?v=uXoh6vi6J5U&feature=youtube_gdata_player", "ka_user_license": "cc-by-nc-sa", "global_id": "v656321710", "sha": "9997c254ec579ab7019c6ecdbb2ce166600189d1", "translated_description": "Happy Pi Day! Also see: Pi is (still) Wrong: http://youtu.be/jG7vhMMXagQ\nPi in Binary Hand Dance: http://youtu.be/OCYZTg3jahU\nSpecial thanks to Toby (or not Toby) for playing Dog Hamlet.\n\nThis cool website lets you search the first 200,000,000 digits of Pi. See if your phone number or encoded name is in there! http://www.angio.net/pi/piquery\n\nSeven Sonnets:\n\nAre Shakespeare's plays encoded within Pi? \nThe truth is: we don't know, but we suspect\nThey're somewhere in those digits. And now I\nWill show why we don't know if we're correct.\n\nYou see, we think the digits do behave\nAs if they were a random sequence, and\nSo many mathematicians tried to brave\nThis question, but we still don't understand.\n\nPi isn't random: each digit must be\nExactly what the definition states.\nIt's pseudo-random, far as we can see,\nBut it's the subject of intense debates.\n\nNow I'll explain, with this parameter:\nIt's all in iambic pentameter.\n\nYou may have heard of this scenario:\nA thousand monkeys type at keyboards 'till\nThey write the works of Shakespeare. Even though,\nIn one life it's a task they can't fulfill.\n\nIf you allow their kids to carry on,\nAll through the generations working hard,\nThey will evolve before they come upon\nA single sonnet written by the Bard.\n\nBut still, the theory's sound! And it is true\nThat with a random and infinite set\nOf letters, that eventu-ally you\nWill find whatever words you want to get.\n\nHowever, on this thing you can depend:\nBefore you do, the universe will end.\n\n\nPi is a number, and that's why I can\nCompletely guarantee no part will be\n9-1-3-7-5-2-2-8-ten\n4-7-9-H-A-M-L-E-T.\n\nYou'd have to make up something, like a code\nWhere zero-one is A, Oh-three is C,\nOr you could also choose some other mode,\nOh-2 could be \"to be or not to be.\"\n\nBut let's go with this system, where a Y\nIs 2-5, O's one five, and R's eighteen,\nAnd next comes zero 9 which is an I,\nOh-three, eleven. Yorick's name is seen!\n\nDoes Pi say anything? How does it go?\n1-4-1-5. I guess the answer's \"no.\"\n\n\nIf you desire to search Pi for a thing\nLike Hamlet, as if you'd 'discover' it,\nWithout a copy used for referencing,\nYou wouldn't know if you'd recovered it.\n\nIn fact, it's almost certain, so beware:\nBefore you get to Hamlet, if you slog\nThrough all the digits, you'll find versions where\nThere's just one thing changed: Hamlet is a dog.\n\nDog Hamlet is so awesome and he goes\nOn infinitely many adventures.\nIn this infinite space everyone knows\nDog Hamlet's king. Sometimes he has dentures.\n\nUnless Pi isn't normal. I'll admit:\nPi might not have a single Dog Hamlet.\n\n\nA normal number is a number where,\nIf you take any pattern of length Z\nYou'll definitely find the pattern there,\nAnd others that length, with' same frequency.\n\nLength 1 would just be every digit, so\nAll digits happen infinity times.\nAnd all two-digit numbers also go\nIn there somewhere. If you list all the primes,\n\nYou get the Copeland-Erdos constant, which\nIs one of few known normal numbers. Or\nTake every number in order and stitch\nThem all together. And we know there's more.\n\nMost numbers must be of the normal kind,\nBut somehow they are hard for us to find.\n\n\nWe think that Pi is normal. Also e\nAnd square root 2 and other stuff like that.\nWe don't know how to prove that they must be,\nThat Pi contains Macbeth where he's a cat.\n\nIf you've got every combination of\nDigits of every length, that will include\nA Romeo and Juliet in love\nWho meet in time and live and end the feud.\n\nAnd since the strings of numbers must occur\nWith equal frequency to other strings\nOf the same length, it don't matter whether\nYou choose this code or other permutings.\n\nPerhaps somewhere Dog Hamlet and Catbeth\nAre chillin', bustin' ghosts, avoiding death.\n\n\nThere's simple open problems about pi,\nLike whether every digit, oh through nine,\nKeeps happening. We can't figure out why\n6 shouldn't stop appearing, down the line.\n\nIt seems ridiculous, to think that 2\nOccurs finitely many times. I fear,\nThat without proof, we can't say it's not true.\nAlas, poor Yorick may never appear.\n\nBut the exciting thing is that I think\nThese problems will be solved before too long.\nAnd then this video will really stink\nBecause all this not-knowing will be wrong.\n\nDon't worry; I look forward to its fall.\n'Till then, a happy Pi Day to you all.", "image_url": "https://img.youtube.com/vi/uXoh6vi6J5U/hqdefault.jpg", "youtube_id": "uXoh6vi6J5U", "content_kind": "Video", "readable_id": "are-shakespeare-s-plays-encoded-within-pi"}], "twitter_url": "", "translated_description": "When you want to make a circle, how is it done? Well you probably will start with the radius one.", "deleted_mod_time": "2013-07-13T00:03:07Z", "logo_image_url": "", "in_knowledge_map": false, "description": "When you want to make a circle, how is it done? Well you probably will start with the radius one.", "x_pos": 0.0, "node_slug": "pi-tau", "deleted": false, "facebook_url": "", "backup_timestamp": "2013-07-13T00:08:13Z", "render_type": "Tutorial", "background_image_url": "", "background_image_caption": "", "assessment_progress_key": "ax0fc1ab8d", "topic_page_url": "/math/recreational-math/vi-hart/pi-tau", "extended_slug": "math/recreational-math/vi-hart/pi-tau", "slug": "pi-tau", "tags": [], "kind": "Topic", "in_topic_browser": false, "sha": "6ae51b6a2c43c5ec72bbe68307e6ee3b9ca7579b", "standalone_title": "About pi and tau", "y_pos": 0.0, "current_revision_key": "6ae51b6a2c43c5ec72bbe68307e6ee3b9ca7579b", "content_kind": "Topic"}, {"icon_src": "", "domain_slug": "math", "relative_url": "/math/recreational-math/vi-hart/singing", "web_url": "", "ka_url": "http://www.khanacademy.org/math/recreational-math/vi-hart/singing", "translated_standalone_title": "Singing (and noises)", "translated_title": "Singing (and noises)", "gplus_url": "", "id": "xde77a66e", "old_key_name": "B-EZRalGRLfHSvQcc0pUzW8BCmqjMlc-8neY9wNK", "hide": false, "title": "Singing (and noises)", "child_data": [{"kind": "Video", "id": 756692482}, {"kind": "Video", "id": 538061176}, {"kind": "Video", "id": 538105060}, {"kind": "Video", "id": "xf320cb16"}], "children": [{"translated_youtube_id": "Av_Us6xHkUc", "relative_url": "/video/doodle-music", "has_questions": false, "keywords": "doodling, mathematics, art, pattern, symmetry, frieze, music, doodle", "ka_url": "http://www.khanacademy.org/video/doodle-music", "duration": 235, "translated_title": "Doodle music", "translated_description_html": "A visual and musical expression of mathematical symmetry groups. The transformations done to the video are equivalent to the transformations done to the notes.\n\nThese type of repeating patterns are called frieze patterns. A couple wallpaper groups are also represented.", "id": "756692482", "description_html": "A visual and musical expression of mathematical symmetry groups. The transformations done to the video are equivalent to the transformations done to the notes.\n\nThese type of repeating patterns are called frieze patterns. A couple wallpaper groups are also represented.", "title": "Doodle music", "progress_key": "v756692482", "edit_slug": "edit/v/756692482", "author_names": ["Vi Hart"], "deleted_mod_time": "2013-07-13T00:03:07Z", "description": "A visual and musical expression of mathematical symmetry groups. The transformations done to the video are equivalent to the transformations done to the notes.\n\nThese type of repeating patterns are called frieze patterns. A couple wallpaper groups are also represented.", "extra_properties": null, "node_slug": "v/doodle-music", "deleted": false, "backup_timestamp": "2013-09-23T10:33:40Z", "date_added": "2012-05-01T18:27:44Z", "download_urls": {"mp4": "http://s3.amazonaws.com/KA-youtube-converted/Av_Us6xHkUc.mp4/Av_Us6xHkUc.mp4", "png": "http://s3.amazonaws.com/KA-youtube-converted/Av_Us6xHkUc.mp4/Av_Us6xHkUc.png", "m3u8": "http://s3.amazonaws.com/KA-youtube-converted/Av_Us6xHkUc.m3u8/Av_Us6xHkUc.m3u8"}, "translated_youtube_lang": "en", "kind": "Video", "url": "http://www.youtube.com/watch?v=Av_Us6xHkUc&feature=youtube_gdata_player", "ka_user_license": "cc-by-nc-sa", "global_id": "v756692482", "sha": "6d711173d20e010cfe4900fdd35b212242509d80", "translated_description": "A visual and musical expression of mathematical symmetry groups. The transformations done to the video are equivalent to the transformations done to the notes.\n\nThese type of repeating patterns are called frieze patterns. A couple wallpaper groups are also represented.", "image_url": "https://img.youtube.com/vi/Av_Us6xHkUc/hqdefault.jpg", "youtube_id": "Av_Us6xHkUc", "content_kind": "Video", "readable_id": "doodle-music"}, {"translated_youtube_id": "OCYZTg3jahU", "relative_url": "/video/binary-hand-dance", "has_questions": false, "keywords": "mathematics, pi, binary", "ka_url": "http://www.khanacademy.org/video/binary-hand-dance", "duration": 148, "translated_title": "Binary hand dance", "translated_description_html": "Thanks to my bro for the music! He's at christopherhart2010@gmail.com\n\nThanks to my other bro for hand dancin' and throwing money at me, and special thanks to my mamma and grandma for their guest appearances.", "id": "538061176", "description_html": "Thanks to my bro for the music! He's at christopherhart2010@gmail.com\n\nThanks to my other bro for hand dancin' and throwing money at me, and special thanks to my mamma and grandma for their guest appearances.", "title": "Binary hand dance", "progress_key": "v538061176", "edit_slug": "edit/v/538061176", "author_names": ["Vi Hart"], "deleted_mod_time": "2013-07-13T00:03:07Z", "description": "Thanks to my bro for the music! 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He's at christopherhart2010@gmail.com\n\nThanks to my other bro for hand dancin' and throwing money at me, and special thanks to my mamma and grandma for their guest appearances.", "image_url": "https://img.youtube.com/vi/OCYZTg3jahU/hqdefault.jpg", "youtube_id": "OCYZTg3jahU", "content_kind": "Video", "readable_id": "binary-hand-dance"}, {"translated_youtube_id": "i_0DXxNeaQ0", "relative_url": "/video/what-is-up-with-noises---the-science-and-mathematics-of-sound--frequency--and-pitch", "has_questions": false, "keywords": "science, mathematics, sound, pitch, frequency, audio, ears, sound wave, music", "ka_url": "http://www.khanacademy.org/video/what-is-up-with-noises---the-science-and-mathematics-of-sound--frequency--and-pitch", "duration": 769, "translated_title": "What is up with noises? (The science and mathematics of sound, frequency, and pitch)", "translated_description_html": "Accuracy not guaranteed. Get Audacity and play! http://audacity.sourceforge.net/\n\nCorrection: it is the \"Basilar\" membrane, which is what I say, but somehow between recording the script and actually drawing the stuff I got confused and thought I just pronounced my Vs poorly. Always sad to have such a simple and glaring error in something I put hundreds of hours of work into, but a \"Vasilar\" membrane can be the kind that a Vi draws to explain Viola Vibrations, I guess! Making up new words is just so prolightfully awstastic.\n\nProps to my Bro for excellent and creative swing pushing, and to my Mamma for filming it.\n\nExtra special thanks to my generous donators, without whom I would not have been able to create this video. Because of your support, I have the equipment, time, and take-out Thai food necessary for doing stuff like this.", "id": "538105060", "description_html": "Accuracy not guaranteed. 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