Welcome to jeffreyellis.org.

About Me

I'm an engineering manager who works at NASA's Johnson Space Center. (Here is my LinkedIn page.) I spent the first 20 years of my career developing highly interactive software for scientific and engineering applications in defense, intelligence, and aerospace. As a manager, I don't get to write much code anymore, so I try to give myself some occasional evening/weekend projects to keep my skills up. See below for some examples. All are available for free download.

The Larch

The Larch is a software tool for creating and editing hiearchical documents, a.k.a. tree documents. Examples of such documents include argument maps, work breakdown structures, hierarchical task analyses, and help documentation. Hierarchical documents are also useful for general note taking.

Ultimate Tic-Tac-Toe

Ultimate Tic-Tac-Toe is an advanced form of Tic-Tac-Toe, where each square in the 3x3 board contains a smaller Tic-Tac-Toe game. You can play 2-player games or against the computer.

Jester: The Song Parody Editor

Jester is a song parody editor with side-by-side display of original and parody lyrics, and a built-in rhyming dictionary. I have big plans for a revamped future version, but not sure that I will ever get the time.


Escape! is a puzzle game that makes you use both sides of your brain.


SSM is my implementation of Schelling's Segregation Model. This example of agent-based modeling illustrates how unexpected macro-level behaviors can emerge in complex systems from the behaviors and interactions of micro-level agents following very simple rules.


Fl_RichTextDisplay and Fl_RichTextEditor are widgets for use with the Fast Lite Toolkit (FLTK), an open-source, multi-platform C++ GUI toolkit available at fltk.org. These text display and editor widgets provide many capabilities not supported by the default FLTK-provided widgets, including hyperlinking, underlining, highlighting, strikethrough, and an undo capability.

Other Stuff

Poor Man's Gantt Chart: I created a template for doing Gantt charts in Microsoft Excel. The Gantt chart is drawn with rows representing tasks and columns representing dates -- i.e., it is NOT an inserted "chart" object within Excel. The timeline for each task is created automatically via Excel's conditional formatting, based on start and end dates. A different color shows the percent complete portion of each task. This "poor man's Gantt chart" is a quick and dirty alternative to more complicated (and expensive) tools such as Microsoft Project. Click here to download the template. It is an .xlsx file, and should work in Excel 2007 and later.