Posts on Dr. Óscar Nájera

E-ballot for Toastmasters speech contests

Fri, 26 Jun 2026 00:00:00 +0000

I spent the last few months building and field-testing a digital ballot system for Toastmasters speech contests, and I’m ready to talk about it in public.

The problem

Paper judging doesn’t scale. A judge fills out a ranking, a ballot counter collects it — breaking the judge’s anonymity in the process — and the counting team retreats to a private room to tally by hand. At small events this is a minor inconvenience. At the joint Area contest I organized this year, expecting a maximum of 66 contestants spread across twelve back-to-back contests hosted in a single 10-hour venue window, manual tallying becomes the bottleneck of the event.

What motivated the recent publishing spree?

Mon, 05 May 2025 00:00:00 +0000

I admire people that write blog posts. Taking the time to put something out there. I want to be like them and share too. This website receives occasional attention, when I really want to say something. Many times, I really want and still fail to do it. It piles on the backlog. This time I had a challenge: 8 posts within a month! About twice a week: challenging but feasible. But as reality would have it, even with some planning I still cram everything to the last moment. There something creative and motivating about pressure and deadlines.

Working for robots

Mon, 05 May 2025 00:00:00 +0000

I self-host some of my git repositories to keep sovereignty and independence from large Internet corporations. Public facing repositories are for everybody, and today that means for robots. Robots are the main consumers of my work. With the AI-hype, I wanted to have a look at what are those AI companies collecting from my work. It is worse than everything, it is idiotically everything. They can’t recognize, that they are parsing git repositories and use the appropriate way of downloading them.

A minimalist Re-frame for ParenScript

Sun, 04 May 2025 00:00:00 +0000

After giving ParenScript another chance I became hopeful of the possibilities for front-end development in Common Lisp. It is not the language it is the tooling, but Lisp is a language that lets you develop your tooling faster. Could I close the gap to the ClojureScript+Reagent+Re-frame ecosystem? Well, optimization is my favorite procrastination, so I might as well give it a try.

Giving ParenScript another chance

Sat, 03 May 2025 00:00:00 +0000

I like programming in Common Lisp. The interactive development style is a nice experience. No matter how painful it is to have moving pieces all the time, the programming loop is much nicer. I know that programming is getting old-fashioned with all the AI assisting tools, so I try to enjoy it while it lasts.

Render checkmk's views on Emacs

Sat, 03 May 2025 00:00:00 +0000

As demonstrated in a previous post , you can query checkmk from Emacs¹. Which turns it into an interface for your data. The next step is to create some basic views of checkmk to skip using its Web UI.

Most of checkmk’s data is tabular, most of its Web UI shows tables. With Emacs-29 the traditional and limited tabulated-list-mode gained an alternative: the vtable (variable pitch tables). It is way more flexible and useful. Instead of being a major mode for a single table in the entire buffer, a vtable can show up anywhere in your buffer and you can even have many on the same buffer.

Query checkmk's livestatus with Emacs

Fri, 02 May 2025 00:00:00 +0000

Checkmk¹ is an IT monitoring software. I used to work for them some time ago and I still use it in my personal live. It provides a Web User Interface(UI) with dashboards to see the status of your monitored system. The way that UI queries they monitoring software is via the livestatus .

Tracking your packages with org-mode

Fri, 02 May 2025 00:00:00 +0000

Emacs is more than my favorite text editor, it is building material. As such, I use it for everything I can, it’s amazing how it always steps up to the challenge!

The internet revived the postal service instead of killing it. Today, I receive more packages than ever before. Tracking where they are doesn’t however fit my workflow. It requires me to open websites, input the tracking id, or at least search for the email with the link. Thus I wondered: Is there a better way to do this in Emacs?

Shavian: The better English script

Thu, 01 May 2025 00:00:00 +0000

English has the worst spelling I know of. It is inconsistent all the way. When someone mispronounces a word, you might think they are avid readers, because it might be the case they learned about the word while reading.

If you listen to a word in English there is no guarantee you’ll be able to spell it. That is certainly why English speaking countries have spelling contests, it is not easy. Neither is it clear after you see a word, whether you’ll be able to pronounce it.

Killing the Bitcoin Lightning experiment

Fri, 17 Jan 2025 00:00:00 +0000

A while ago, I got all excited around the idea of Bitcoin as art . It was such a satisfying perspective that I decided to embrace it and implement a tipping service on the Bitcoin Testnet for this website. A fun experiment, a way to learn something and tinker around with the technology. The best part was: it somehow didn’t require any maintenance. It would work without further tinkering.

The Law by Frédéric Bastiat

Fri, 22 Dec 2023 00:00:00 +0000

There is nothing like the filter of time. When a book from 1850 receives praise, you know its insight is timeless and its quality undeniable. This essay discusses what the law should be and shows the tragedy of what it has become. The content still relevant today, reminds us of how the more things change, the more they stay the same.

Upgrading this blog again

Wed, 01 Nov 2023 00:00:00 +0000

Web development is the skill that irritates me the most. It has improved over the years. The tools available today are far superior. But, I only glimpse at better web design skills. I often times struggle to understand why some websites look the way they do. Even with full access to their source code, replicating them isn’t always evident. There are HTML & CSS tricks I refuse to practice in the aim of simplifying what I imitate. That means some layouts don’t look exactly the same.

Setup up a Bitcoin Lightning point of sale in Common Lisp

Thu, 30 Mar 2023 00:00:00 +0000

Because I can, I recently added support for testnet Bitcoin Lightning payments into this website. The beauty of Freedom and privacy respecting software is that you can do anything you want with it. There are many ways to do it. You can always use a service, provider for that, but the beauty of Bitcoin, the reason it is valuable, is that you can do it yourself.

Bitcoin is art

Fri, 24 Mar 2023 00:00:00 +0000

Bitcoin is this strange thing I don’t fully understand. Going down the rabbit hole, as it is commonly known, I generally feel disappointed. Every bitcoiner I meet is a fanatic insisting that I buy bitcoin instead of a supportive mentor. The best buys of my life took place under guidance not pressure, thus I’m always reluctant to listen. Why are they constantly trying to sell it to you?

Why colorize terminal output when you can colorize on the reader?

Tue, 29 Nov 2022 00:00:00 +0000

Colorful text is a must, because we are visual creatures. We process shapes and colors way better than symbols. Confronted to a screen full of text, it is hard to make sense of it, without meaningful coloring. I even find pure text repulsive, I don’t want to look. Command like tools like ls, grep, git offer colorized output, in fact I’m only able to find them useful, when their output is colorful. Color demands attention and focuses it too.

Preventing the collapse of civilization

Fri, 19 Aug 2022 00:00:00 +0000

I stumbled upon this talk by Jonathan Blow on YouTube and I must share it. Civilizations flourish thanks to the technologies they invent. Yet those same technological achievements get lost because the same civilizations that created them fail or at least they fail to propagate them to the future. We open ourselves to those same vulnerabilities over and over again.

Elliptic Curve Digital Signature Algorithm - Bitcoin & Haskell

Wed, 04 Aug 2021 00:00:00 +0000

The previous posts covered mathematical curiosities. Now we can leave that realm, find an application and turn them into tools to work with elliptic curve cryptography. That means finding and choosing which particular values of the parameters bring us into a curve we can use for cryptography.

Elliptic Curves on Finite Fields - Bitcoin & Haskell

Tue, 13 Jul 2021 00:00:00 +0000

When merging the last two posts, I immediately run into serious difficulties. Haskell’s type system just made my work harder(well my ignorance did). Until I could come up with a solution, I could not appreciate how the strictness of the type system actually gives flexibility.

Elliptic Curves - Bitcoin & Haskell

Sun, 02 May 2021 00:00:00 +0000

In this series of posts I’m solving the exercises of Programming Bitcoin¹ in Haskell, I’m learning Bitcoin and Haskell in one go.

To describe a point in the elliptic curve, we need four data points. \((x, y)\) are the coordinates themselves, additionally we need the constants \((a, b)\) that define the elliptic curve given by the equation \(y^2 = x^3 + ax +b\). Finally, there is the special case of the point at infinity, which does not really fit in the previous constrain. In other languages I would just describe with an invalid or null value, in Python for example I would use the None value in both \((x, y)\) coordinates, yet in Haskell it can be beautifully defined as an element of the type. That is certainly a killer feature of the language, and I expect to be using it more often.

Finite Fields - Bitcoin & Haskell

Sat, 17 Apr 2021 00:00:00 +0000

Bitcoin’s price has gone crazy up, and now I’m really responsible for learning it. I found the book Programming Bitcoin¹ by Jimmy Song, it looks good enough to give it a try. It uses Python to teach, which is uninteresting and I end up only skimming over it, which leads to low retention. Learning necessitates inefficiencies, trial and error, solving problems and sharing. Thus to learn I need to throw an extra challenge. I’m going to learn another programming language(Haskell) to solve the book’s problems.

Why swim in a river at 0°C?

Sat, 09 Jan 2021 00:00:00 +0000

There are plenty of reasons: Get out of your comfort zone, build character, discover your limits. There are plenty of justifications: Simply crazy, settling a bet, religious penitence/purification.

All those might apply, however for me it is a CELEBRATION. A celebration of how well I’m doing nowadays. I was born in a big city, I grew up surrounded by the grayness of concrete. The river in my city was so polluted that its smell alone would keep you away. Going into nature implied a family trip, implied planning, implied getting everyone to agree and then traveling far away until we could reach a clean river, a waterfall or a lake. Only then could I jump into those clean, refreshing and relaxing waters. In those day it didn’t matter how cold they were.

Getting started with bitcoin

Wed, 16 Dec 2020 00:00:00 +0000

Bitcoin is all over the news, this time with big investors pouring money into it, a global pandemic that put the economy on hold, and governments printing money like crazy. Price raises, it is a bubble again.

Maybe it is responsible this time to at least try to learn about Bitcoin without rushing to get it like everybody else seems to be doing again. The only way to learn about it, benefit from it and clear the doubts from the healthy skepticism is to test the technology by yourself. This is my experience setting up a node.

Guile macros - avoiding code duplication when interfacing to notmuch

Fri, 04 Dec 2020 00:00:00 +0000

When working on the interface to notmuch I stumbled upon the case where iterating over messages and iterating over filenames produced the same code structure only changing the functions being used. I hate to see code duplication and thus I went out exploring for solutions available in Guile to solve this issue.

Managing my email with Guile - interfacing to notmuch's C library

Thu, 03 Dec 2020 00:00:00 +0000

Manually creating the bindings for a sizable C program is a lot of work, also it is not very rewarding. I’m lazy and don’t want to do that. I looked around for what other options I have and I was surprised about the solution.

Guile's Foreign Function Interface - linking to notmuch

Wed, 02 Dec 2020 00:00:00 +0000

On the previous post I covered how I can call external programs as new processes and interact with their inputs or outputs. Here I will use directly the foreign libraries written in C using Guile’s foreign function interface .

In this series of posts I record how to use Guile as a scripting language and solve various tasks related to email work.

Managing my email with Guile - A shell script alternative

Tue, 01 Dec 2020 00:00:00 +0000

Most of the pre-processing work of my emails was already solved with a combination of a bash script, which uses the notmuch cli and the python package afew . However, I’m learning Guile and I need a real task to solve to practice the language.

Attachment files in plain text accounting

Fri, 13 Nov 2020 00:00:00 +0000

I have been using ledger to keep track of my expenses. It is simple, it doesn’t interfere with my workflow, and I can edit data with my favorite text editor Emacs, because ledger only deals with plain text files. I love this workflow.

Fun with Rofi and Guile - A minimal habit tracker

Thu, 15 Oct 2020 00:00:00 +0000

In my personal project to learn LISP, I decided to try GNU Guile . It is a Scheme implementation and it is the official extension language of the GNU project . To learn, my first step is to actually use it, and my first minimal toy project, will be a Habit tracker. There are plenty habit trackers around, to make another one, yet this is just mine, done for my personal joy of implementing it in a language I’m trying to learn.

How To Escape Poverty? - Is Your Thinking Keeping You Poor?

Sun, 19 Apr 2020 00:00:00 +0000

I stumbled upon this talk by Douglas Kruger on YouTube. I decided to take notes and write my own summary to deepen the learning experience. It provides me with a reference for later times. Douglas Kruger mentions 8 points, I reorganized them into 5 themes.

Nerd Humor: English - The torture of the conqueror

Fri, 29 Nov 2019 00:00:00 +0000

On November 16^th 2019, I held a short humorous speech at the Wordstock festival in Nuremberg-Germany. I never imagined getting this far, and now I only see it as the beginning. In humor and comedy, I have always been on the spectator side. However, this year I chose to develop myself in public speaking and it indeed has been a long way. It all started as a personal challenge. I began by signing up in my public speaking club Isar-Speak .

Me as of today

Sat, 03 Aug 2019 00:00:00 +0000

Hello everyone, I’m starting a new section of my life and I want to engage on new projects. But before jumping into anything new, I want to review where I stand and what I can tell you about myself.

My talk at the 18. Augsburger Linux-Infotag 2019

Sun, 07 Jul 2019 00:00:00 +0000

I have always been a Free Software fan and I’m always happy to participate in events where I meet like minded people. Linux days are a great opportunity for this. They are super fun and still hold the free software spirit about sharing your knowledge and learning from others. They are also organized by volunteers, which deepens the nice feeling of community. I found one of these events. The 18. Augsburger Linux-Infotag 2019 would take place in the neighboring city of Augsburg in Germany . Since I was going participate the company I work with proposed me if I could give a talk about our product. Without giving much thought to it I just agreed. Dare first to do the things then figure out the way.

Bornhack 2018

Sun, 26 Aug 2018 00:00:00 +0000

How do you take your summer holidays? Some seek rest by laying down the sun like an iguana warming up their blood. Just doing nothing to compensate for the hard work over the year. I’m not against that, I do it too. But I found a new alternative, you can go out and learn something new. Only a year ago I discovered hacker camps, an outdoor tent camp event for hackers and makers.

Forgetting - Our filter for the irrelevant

Tue, 31 Jul 2018 00:00:00 +0000

I just stumbled upon this article: To Remember, the Brain Must Actively Forget | Quanta Magazine , and it served me as quite a confirmation bias. I always reflected why it is so hard to learn something, or remember something. Consider, what a great super power it would be to remember it all. The true new point of view for me here is the merit of forgetting.

It's not about having a backup, but being sure the backup works

Tue, 05 Jun 2018 00:00:00 +0000

Since I discovered BorgBackup (short: Borg) I have felt way more confident about my backups. Borg gives you a space efficient storage of backups, data is saved encrypted, and you get good versioning of backups. I solved all my previous inconveniences when just using rsync. I lacked the way to keep track and order different versions. Compression and encryption as a great plus even when I just keep my backups locally.

Participating to my first hackathon

Thu, 17 May 2018 00:00:00 +0000

I’m currently looking for my next life project and to figure it out I trying a lot of stuff. To that goal I’m getting involved in as many things as possible. Last week, I went to the Innolabs healthcare hackathon in Berlin . It was quite an awesome event and I learned a lot from it. I never really worked on the health sector before, thus it was a nice introductory experience.

Org-CV an Org export backend for CV

Sun, 06 May 2018 00:00:00 +0000

I’m again in this time of my life where I’m looking for a new long term project to work on. Because optimization is my favorite way of procrastination, instead of just making a Curriculum Vitae (CV) for job applications, I decided that I need to implement an org-mode export backend. This backend will let me keep my CV in org-mode and then export it to \(\LaTeX\) or markdown for my website. This exporter now lives in gitlab as org-cv and the documentation is here .

A year on my cloud

Fri, 04 May 2018 00:00:00 +0000

It has been a very complicated year regarding my cloud services. I started completely unaware of the difficulties, and it has been a fun and painful ride. The fact that there are projects aiming to provide personally controlled cloud services is great. The fact that there is people being paid for doing this kind of work for companies means that it ain’t that simple to manage.

Visualizing a Bethe lattice

Thu, 11 Jan 2018 00:00:00 +0000

During my PhD I always wanted to have an interactive way of plotting a nice looking Bethe Lattice and particular to my work a Dimer Bethe lattice. Because this visualization wasn’t an essential part of my research I never investigated into it. It is enough to draw them on paper for any practical purpose. I was then confronted with my PhD oral presentation, great opportunity to procrastinate and get the nice unessential plots done. They didn’t end in the final version of the presentation(again is not the fundamental part of my work), but I wanted to share them anyway.

Git diff images and pdfs

Mon, 13 Nov 2017 00:00:00 +0000

Git is a fantastic tool to version control code. And the advantages of version controlling my work are so evident that I want to version control everything else I do besides code. Most of my work consists of editing text files, and I have even forced my workflow into text files just to be able to version control more of it. Thus, I keep track of my source code, org-mode notes and then some \(\LaTeX\) files.

Moving to Hugo and GitLab pages

Wed, 01 Nov 2017 00:00:00 +0000

I’m guilty of having this online blog and not writing on it. I confess that working on its looks and internals is way more fun for me than actually writing some words in plain English for everyone to read. That however misses the point, because it is the blog post that justify the blog, not its internals.

American Physical Society March Meeting 2017

Mon, 20 Mar 2017 00:00:00 +0000

This March I had the opportunity to go to the American Physical Society March Meeting in New Orleans. Since everyone gets a time slot for a talk, I got my chance too. It was scheduled too early and I didn’t enjoy a big audience which lowered my stress levels. It was the first day so that I could enjoy the rest of my time talking with other people instead of stressing about my talk.

The right dictionary

Sun, 15 Jan 2017 00:00:00 +0000

I just found a post on using the right dictionary and I immediately had to review its reference: You’re probably using the wrong dictionary by James Somers . I don’t regret it. The core message is that we shall not only use dictionaries to find the meaning of words we don’t know, but to use them to enrich our prose. I never considered there would be such a dictionary that allows for such kind task. James presents the Webster’s Revised Unabridged Dictionary, unfortunately that link is broken. Nevertheless he provides a link to download the dictionary , it a standard format for dictionaries.

EuroScipy 2016

Tue, 30 Aug 2016 00:00:00 +0000

Sphinx-Gallery is an amazing project, and I got to talk about it in the EuroScipy 2016. Which is great for the experience

Here I embed the presentation for convenience.

You can find the full screen version of the presentation at:

Choosing a text editor to match my workflow

Sun, 06 Dec 2015 00:00:00 +0000

TL;DR Emacs is the way to go

Optimization is my way of procrastination. This time it is about getting a decent text editor. I am at the point where it is just annoying that all my text is getting scattered between different editors and that many times I have to open my same files under different editors to get what I need done.

Using Cython in real case example

Tue, 07 Apr 2015 00:00:00 +0000

Python has become my preferred language when it comes to programing. It is so simple to import from its vast library of packages and then build upon them to get things working. Yet, at some point, when all the design phase is over, and the software has to perform it is so slow.

Using a Framework for web development

Sun, 15 Feb 2015 00:00:00 +0000

This comes after an old idea, that has been bugging me in the last years: “I can’t do everything myself anymore, there is just no time for such thing”. I’m not a specialist in everything, I chose to focus long ago in physics. Thus, for all those web development things I can’t do them on my own anymore. I have to use framework and templates.

Website redo and blog migration

Sun, 12 Oct 2014 00:00:00 +0000

Today my website experienced a complete redo with a new design. The previous presentation was established to mimic my blogger site. That required a great amount of effort because I like simple things and to simplify the blogger theme was quite challenging, I not always get CSS do what I want. Also the web site could be seen in web browser but gave already problems in mobile phone browsers, and doing the translation of the blogger site version for mobiles was an unwanted challenge.

Third Post

Tue, 10 Sep 2013 00:00:00 +0000

I’ll aim at not counting mi posts for future releases of content. But for now, since this look more like biographical notes of my life I can’t find better titles for the posts. It’s also because I’m not packing just one subject but some history of my live in the last time.

Second Post

Thu, 01 Aug 2013 00:00:00 +0000

On my first post after blog opening, I offered to write as often as possible to record my learning and share ut. Unfortunately, even for me, it has not happened. This is the second post. That does not mean, I spend my time without getting new knowledge. It means instead that I still need to practice about this blogging task and discipline myself to it. Certainly the lack of monetary income hinders me from publishing. Hope to change this, and that it doesn’t take other many months for the third post.

Start now

Sat, 13 Oct 2012 00:00:00 +0000

This is the first of many posts to come. I don’t now how often I will publish new information, but I make a try to write about things I have done and learned of often as possible.

Right now this is just a test, on how blogger works. I will try to merge the design with my website for an unified look. I’m not a designer so my website is ugly, but with time, effort and helping comments I will make it good looking.