lossless compression algorithm and format (command line utility)

brotli

lossless compression algorithm and format (command line utility)

Brotli is a generic-purpose lossless compression algorithm that compresses data using a combination of a modern variant of the LZ77 algorithm, Huffman coding and 2nd order context modeling, with a compression ratio comparable to the best currently available general-purpose compression methods. It is similar in speed with deflate but offers more dense compression.
running guile on emacs in geiser mode

guile-2.0

GNU extension language and Scheme interpreter

Guile is a Scheme implementation designed for real world programming, providing a rich Unix interface, a module system, an interpreter, and many extension languages. Guile can be used as a standard #! style interpreter, via #!/usr/bin/guile, or as an extension language for other applications via libguile.
SyFi Form Compiler

sfc

SyFi Form Compiler

Main text interface of Smuxi

smuxi-frontend-stfl

STFL frontend for Smuxi (experimental)

Smuxi is an irssi-inspired, flexible, user-friendly and cross-platform IRC client for sophisticated users, targeting the GNOME desktop.
Screemshot showing a typical Dia screen

dia-shapes

Diagram editor (additional shapes)

Dia is an editor for diagrams, graphs, charts etc. There is support for UML static structure diagrams (class diagrams), Entity-Relationship diagrams, network diagrams and much more. Diagrams can be exported to postscript and many other formats.
program to create 3D geometry from Python scripts.

pyformex

program to create 3D geometry from Python scripts.

pyFormex can be used to generate, transform and manipulate large geometrical models of 3D structures by sequences of mathematical operations. Unlike traditional CAD systems, pyFormex provides a powerful (Python based) scripting language as the basic user input, making it very well suited for automated and repeated (parametric) design procedures. It provides a wide range of operations on meshes, like STL type triangulated surfaces and FEA or CFD grids. Nurbs curves and surfaces are under development. pyFormex is often used to create models from medical scan images, or as a pre- and post-processor for Finite Element analysis programs. But it could just as well be used to just create some nice 3D renderings.