Justin Meiners Site

Take your time 11/24/2025 I’m someone who likes to work a little slower, explore a subject in-depth, and always go back to basics.

Water Hammer Arrestor 08/02/25 I’m back with another house maintenance project (and not talking about computer technology).

Replacing hardboard siding 06/21/2025 This summer I replaced part of the siding on my 1970s house in Boulder.

Building Scanning Patents At a previous startup, I invented an Augmented Reality (AR) system for scanning buildings, and automatically extracting floor plans from scans.

Thinking styles from math 11/18/2022 A surprising lesson I learned from graduate school is that math is just very different than everything else I have tried learning in the past.

Iterating grid cell neighbors 10/27/22 Suppose we need to iterate over the neighbors of a cell in a 2D grid: * * * * - * * * * This can be done with the following well known pattern: void all_neighbors() { for (int i = -1; i <= 1; ++i) { for…

The Quake entity system: shell scripting for games By: Justin Meiners 07/20/2022 The Quake engine provided the foundation for many early 3D games, including contributions to hit titles like Half-Life, Call of Duty, and Star Wars Jedi Knight II: Jedi Outca…

A simple mesh adjacency data structure 06/25/2022 Do you need a mesh adjacency structure?

Learn multi-variable optimization by creating a drawing assistant.

Literate programming is much more than commenting code 03/07/22 Most programmers haven’t heard of literate programming, and the few that have tend to think it means writing a lot of comments around your code.

Deploying Common Lisp Scripts 3/05/22 Do you want a Common Lisp workflow like Python or Perl?

Paint program for Unix.

Almost Solving the Halting Problem By: Justin Meiners The halting problem is to devise a method that can determine whether a given Turing machine terminates in a finite amount of time.

Swift Proposal: Balanced Binary Reduction By: Justin Meiners 06/14/2021 Introduction Swift’s reduce can be used to accumulate elements in a sequence.

Three Myths about Passive Investing 5/3/2021 Stock markets are at tremendous highs, not only in absolute price, but also in terms of earnings yield.

Advent of Code 2020 Day 18: Rethinking Operator Precedence 12/27/20 Part 2 of AOC Day 18 asks you to evaluate some math expressions, but with a twist. + has a greater operator precedence than *.

Advent of Code 2020 Day 19: An Easy way to do Part 2 12/19/20 A fun mechanic in AOC is that the problem is divided into two parts, with the second only revealed after completion of the first.

The Universal Property of Quotients 11/15/20 The first time you encounter a theorem concluding with “an arrow that makes the diagram commute” can be quite confusing.

Questioning Probability 10/8/20 Are Elections Actually Random?

Understanding LINQ GroupBy 09/26/20 As a C# programmer, you are probably familiar with Select, Where, and Aggregate, the LINQ equivalents of the fundamental functional programming operations map, filter, and reduce.

Boring Benefits of Lisp 10/07/20 Lisp advocates are famous for having elaborate reasons for why Lisp is their favorite language.

10 Hard Decisions: A Model for Programmer Productivity 09/26/20 How do you ensure that programmers are using time effectively?

Keeping Up-to-date 1/23/2020 The software industry is synonmous with rapid innovation.

MultiplyPoint3x4 in Unity 01/21/2020 What is the difference between MultiplyPoint and MultiplyPoint3x4 in Unity3D?

Think in Math.

Notes on Vector Libraries 05/12/2019 A good vector math library is essential for graphics and simulation programming.

Foundation of Math Reading List 04/13/2019 One of my favorite courses in college was philosophy of language.

The Skills Poor Programmers Lack 02/22/2019 Updated: 04/27/2020 A friend and I had a discussion about the basic skills that are often lacking in experienced programmers.

Write your own virtual machine for the LC-3 computer!

Modern OpenGL These are notes sent to a friend, not a formal article.

HoloLens First Impressions 11/10/2016 At work, I recently started on a new medical application for the Microsoft HoloLens.

3D Paint 10/30/16 In 2012 I came across the paper OverCoat: An Implicit Canvas for 3D Painting which describes a technique for creating 3D models using traditional painting methods.

Old Artwork 10/15/2015 I am not much of a visual artist, but I still enjoy 3D modeling and animation.

Old Games 10/09/2015 I spent quite a bit of time experimenting with game technology when I was first learning how to program.