Earth orbits and satellite coverage display in 3D on your laptop.
SaVi - simulate Starlink, Iridium, Globalstar, O3b, GPS, Galileo and other satellite constellations, modify them, or design your own. Requires Tcl/Tk and Unix libraries; 3D viewing option requires Geomview running on X Window.
PLplot is a cross-platform, scientific graphics plotting library that supports math symbols and human languages (via UTF-8 user input strings); plot capabilities for multiple non-interactive plot file formats and in multiple interactive environments; and bindings for multiple computer languages.
tkBacktracer is a cross-platform interactive visualization tool to explore the tool motions in RS-274D "G-code" CNC files used in computer controlled milling and manufacturing.