Arduinoで作る浮遊光球
Instructablesに 「Levitating Death Star」 という記事があります。市販の浮遊地球儀を使って、「デス・スター」の模型を作ったものです。美しいビジュアルもさることながら、使用した地球儀に関心をそそられました。そこで早速、永久磁石を複数使って静的な浮上を試してみたのですが、これは難しいことが分かりました（*）。 （*）Webで調べると、この困難は「アーンショウの定理」（参考A、参考B）で保証されているようです。一方で、この定理の間隙を縫った知育玩具もあるようです（参考C）。 そこで、電磁石とArduinoを使って新たな工作を行うことにしました。上記の記事と差異は下記の3点です。 既製の市販品は（なるべく）使わない 球体の回転を持続させる 球体に電池を入れない VIDEO(1): 浮遊球体の回転、発光、点滅 ここでは最初の浮上トライアルから、室内装飾としての組み立
Announcing Remacs: Porting Emacs to Rust | Hacker News
The example seems to be wrong https://github.com/Wilfred/remacs#porting-c-functions-to-rus...fn Fnumberp(object: LispObject) -> LispObject { if lisp::SYMBOLP(object) { unsafe { Qt } } else { Qnil } } It uses SYMBOLP instead of NUMBERP. Highlighting the risk of introducing new bugs. Which leads to the question, why Remacs can't just auto-wrap the lisp::* functions, which I assume are the Rust versi
Insights | Nearform
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An Interview With Haskell Developer Edward Kmett
Now this still requires me to find a choice of basis for each vector space, but it just so happens that lenses can provide a canonical choice of such a basis. And the nice thing is I can use typeclasses to share such lenses between different vector spaces. By giving names to the ‘x’ dimension or ‘y’ dimension. I can share those names across 2d and 3d vectors for convenience. I’d originally planned
Reagent deep dive part 1: Hiccup and ratoms
Today I invite you to embark with me on the grand tour of Reagent, a ClojureScript library for building web pages. I will be encouraging you to try several small exercises on this page as we go. You can change the example code provided on this page to make it do other stuff. Let me know in the comments if you get stuck at all, or have any questions. This tour is going to get down into the nitty gr
Announcing Tokio 0.1
Today we are publishing the preliminary version of the Tokio stack, 0.1! Tokio is a platform for writing fast networking code in Rust. It’s built on futures, a zero-cost abstraction for asynchronous programming in Rust . It provides a suite of basic tools, tokio-core , for asynchronous I/O with futures. It also provide a higher-level layer, tokio-proto , for easily building sophisticated servers a
Fast Haskell: Competing with C at parsing XML
In this post we’re going to look at parsing XML in Haskell, how it compares with an efficient C parser, and steps you can take in Haskell to build a fast library from the ground up. We’re going to get fairly detailed and get our hands dirty. A new kid on the block A few weeks ago Neil Mitchell posted a blog post about a new XML library that he’d written. The parser is written in C, and the API is
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【雨鳥ユウイオリジナル】IMAGES【UTAU】
Radamés Gnattali: Dez estudos para violão solo (Guitar: Vitor Garbelotto)
Toni Edelmann in Maisema / Landscape form 1982 Finland
Jigsaw - Puzzle from 1981 Germany
A proposition is the (homotopy) type of its proofs
Tamonさんの「鉄道敷設法予定線全線開通図」がすごい
The complexity of abstract machines | Lambda the Ultimate