<?xml version="1.0" encoding="UTF-8"?><rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom" version="2.0" xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd" xmlns:googleplay="http://www.google.com/schemas/play-podcasts/1.0"><channel><title><![CDATA[Demetri Spanos]]></title><description><![CDATA[Intersections of mathematics, computing, and design]]></description><link>https://demetri.substack.com</link><image><url>https://substackcdn.com/image/fetch/$s_!jdih!,w_256,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fdemetri.substack.com%2Fimg%2Fsubstack.png</url><title>Demetri Spanos</title><link>https://demetri.substack.com</link></image><generator>Substack</generator><lastBuildDate>Sun, 17 May 2026 10:28:08 GMT</lastBuildDate><atom:link href="https://demetri.substack.com/feed" rel="self" type="application/rss+xml"/><copyright><![CDATA[Demetri Spanos]]></copyright><language><![CDATA[en]]></language><webMaster><![CDATA[demetri@substack.com]]></webMaster><itunes:owner><itunes:email><![CDATA[demetri@substack.com]]></itunes:email><itunes:name><![CDATA[Demetri Spanos]]></itunes:name></itunes:owner><itunes:author><![CDATA[Demetri Spanos]]></itunes:author><googleplay:owner><![CDATA[demetri@substack.com]]></googleplay:owner><googleplay:email><![CDATA[demetri@substack.com]]></googleplay:email><googleplay:author><![CDATA[Demetri Spanos]]></googleplay:author><itunes:block><![CDATA[Yes]]></itunes:block><item><title><![CDATA[New Consolidated Website, but Keep Following on SubStack]]></title><description><![CDATA[No Action Needed for SubStack Followers]]></description><link>https://demetri.substack.com/p/new-consolidated-website-but-keep</link><guid isPermaLink="false">https://demetri.substack.com/p/new-consolidated-website-but-keep</guid><dc:creator><![CDATA[Demetri Spanos]]></dc:creator><pubDate>Thu, 12 Feb 2026 15:08:26 GMT</pubDate><enclosure url="https://substackcdn.com/image/fetch/$s_!w-gP!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png" length="0" type="image/jpeg"/><content:encoded><![CDATA[<div class="captioned-image-container"><figure><a class="image-link image2 is-viewable-img" target="_blank" href="https://substackcdn.com/image/fetch/$s_!w-gP!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png" data-component-name="Image2ToDOM"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!w-gP!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png 424w, https://substackcdn.com/image/fetch/$s_!w-gP!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png 848w, https://substackcdn.com/image/fetch/$s_!w-gP!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png 1272w, https://substackcdn.com/image/fetch/$s_!w-gP!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png 1456w" sizes="100vw"><img src="https://substackcdn.com/image/fetch/$s_!w-gP!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png" width="728" height="470.5" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:false,&quot;imageSize&quot;:&quot;normal&quot;,&quot;height&quot;:941,&quot;width&quot;:1456,&quot;resizeWidth&quot;:728,&quot;bytes&quot;:2504704,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:false,&quot;topImage&quot;:true,&quot;internalRedirect&quot;:&quot;https://demetri.substack.com/i/187662313?img=https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png&quot;,&quot;isProcessing&quot;:false,&quot;align&quot;:&quot;center&quot;,&quot;offset&quot;:false}" class="sizing-normal" alt="" srcset="https://substackcdn.com/image/fetch/$s_!w-gP!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png 424w, https://substackcdn.com/image/fetch/$s_!w-gP!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png 848w, https://substackcdn.com/image/fetch/$s_!w-gP!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png 1272w, https://substackcdn.com/image/fetch/$s_!w-gP!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F1ccd65bc-c58e-4790-aa54-5bf534171af0_2430x1570.png 1456w" sizes="100vw" fetchpriority="high"></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg role="img" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><title></title><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a></figure></div><p><em>If you are already following here on SubStack, you do not need to do anything. You can stop reading now if you like.</em></p><p>I&#8217;m consolidating the <a href="https://demetrispanos.com">web presence</a> for my main activities:</p><ul><li><p>Math for the Working Programmer (&#8220;course&#8221;)</p></li><li><p>No Royal Road (&#8220;book&#8221;)</p></li><li><p>Personal Research / Articles / Demos</p></li><li><p>Business Requests (Mathematical Computing / AI Engineering)</p></li></ul><p>This is partly for convenience, and partly to publish content that SubStack (still!) cannot host reasonably &#8212; for example: interactive figures, ZIP files of code.</p><p>I will send all new content both to SubStack (so you can follow by email, mobile app, or RSS) and to <a href="https://x.com/DemetriSpanos">my account on X.com</a>.</p><p>Again, <em>you do not need to do anything if you are already following here on SubStack.</em></p><p></p>]]></content:encoded></item><item><title><![CDATA[NR2 component launch: LibQuincy (Handmade Seattle 2022)]]></title><description><![CDATA[I just did a demo of LibQuincy, an audio visualizer focused on human perception, at Handmade Seattle 2022.]]></description><link>https://demetri.substack.com/p/nr2-component-launch-libquincy-handmade</link><guid isPermaLink="false">https://demetri.substack.com/p/nr2-component-launch-libquincy-handmade</guid><dc:creator><![CDATA[Demetri Spanos]]></dc:creator><pubDate>Wed, 16 Nov 2022 21:56:22 GMT</pubDate><enclosure url="https://substackcdn.com/image/fetch/$s_!OqIb!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F3089e4fe-d0f7-4f00-b307-64ef8b4f6ecd_1536x534.png" length="0" type="image/jpeg"/><content:encoded><![CDATA[<p>I just did a demo of <a href="https://github.com/demetri/libquincy">LibQuinc</a>y, an audio visualizer focused on human perception, at Handmade Seattle 2022. [Dec 1 Update: You can now watch the full-resolution <a href="https://guide.handmade-seattle.com/c/2022/libquincy/">conference video</a>.]</p><p>You can see some technical details at the GitHub link, but here I want to talk about LibQuincy&#8217;s relationship to my upcoming interactive mathematics education project: No Royal Road (NR2).</p><div class="captioned-image-container"><figure><a class="image-link image2 is-viewable-img" target="_blank" href="https://substackcdn.com/image/fetch/$s_!OqIb!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F3089e4fe-d0f7-4f00-b307-64ef8b4f6ecd_1536x534.png" data-component-name="Image2ToDOM"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!OqIb!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F3089e4fe-d0f7-4f00-b307-64ef8b4f6ecd_1536x534.png 424w, https://substackcdn.com/image/fetch/$s_!OqIb!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F3089e4fe-d0f7-4f00-b307-64ef8b4f6ecd_1536x534.png 848w, https://substackcdn.com/image/fetch/$s_!OqIb!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F3089e4fe-d0f7-4f00-b307-64ef8b4f6ecd_1536x534.png 1272w, 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https://substackcdn.com/image/fetch/$s_!OqIb!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F3089e4fe-d0f7-4f00-b307-64ef8b4f6ecd_1536x534.png 848w, https://substackcdn.com/image/fetch/$s_!OqIb!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F3089e4fe-d0f7-4f00-b307-64ef8b4f6ecd_1536x534.png 1272w, https://substackcdn.com/image/fetch/$s_!OqIb!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2F3089e4fe-d0f7-4f00-b307-64ef8b4f6ecd_1536x534.png 1456w" sizes="100vw" fetchpriority="high"></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg role="img" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><title></title><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a></figure></div><p>First, two background points</p><ul><li><p>NR2 is, for lack of a better genre term, a &#8220;math game&#8221; that will have an Early Access release sometime around Q2 2023. I will probably do a crowdfund for it in the interim. If any of this interests you, you can follow these posts on Substack, or <a href="http://demetri.substack.com/feed">RSS</a>. You can also follow me on <a href="https://twitter.com/DemetriSpanos">Twitter</a> for math / science / education / programming discussion.</p></li><li><p>NR2 will have many subsystems that I will release as open source as they are finished. LibQuincy is the first such system. In the future I will also, at a minimum, eventually release the mathematical typesetting and text rendering system (a lightweight alternative to LaTeX designed specifically for interactive media).</p></li></ul><p>LibQuincy fell out of making NR2 because I wanted an interactive, intuitive, demonstration of various abstract concepts of linear algebra. This subject is actually fairly deep, but I can give you a small taste quickly: in the same way that you can move North or South without moving East or West, you can hear a high frequency while simultaneously hearing a low frequency. This is a generalized concept of orthogonality that lifts us from spatial metaphors of right angles, and moves us to broader principles like separation and independence. Indeed this generalized idea of orthogonality is the foundation for Fourier Series, and almost all image and video encoding.</p><p>While LibQuincy started as a simple byproduct of NR2, it revealed an opportunity to design an audio visualization library based on human perception. At the risk of overgeneralizing, most spectral visualizers are oriented either around mathematical concerns like signal representation, or around sound engineering concerns like filtering. These are important activities, but I&#8217;ve always found them insufficient in service of Quincy&#8217;s mission statement: &#8220;See What You Hear&#8221;. This has led to much productive reading on human sound perception, how best to represent that with mathematical tools, <em>and</em> with tools of visual design. Again, you can see technical details at the <a href="https://github.com/demetri/libquincy">GitHub</a> project.</p><div class="subscription-widget-wrap-editor" data-attrs="{&quot;url&quot;:&quot;https://demetri.substack.com/subscribe?&quot;,&quot;text&quot;:&quot;Subscribe&quot;,&quot;language&quot;:&quot;en&quot;}" data-component-name="SubscribeWidgetToDOM"><div class="subscription-widget show-subscribe"><div class="preamble"><p class="cta-caption">If you like, Substack can notify you of future posts by email. There is also <a href="http://demetri.substack.com/feed">RSS</a> and <a href="http://twitter.com/DemetriSpanos">Twitter</a>.</p></div><form class="subscription-widget-subscribe"><input type="email" class="email-input" name="email" placeholder="Type your email&#8230;" tabindex="-1"><input type="submit" class="button primary" value="Subscribe"><div class="fake-input-wrapper"><div class="fake-input"></div><div class="fake-button"></div></div></form></div></div>]]></content:encoded></item></channel></rss>