A graphical Finite State Machine (FSM) designer.
Jade is a cross-platform diagram editor built on the Qt framework.
Free drawing software for Windows, Mac OS X, and Linux
Interactive designer for Celtic knots
Not your usual Architectural Modeler
Output Processing script from Java AWT/Swing paint call
Advanced script editor IDE for squirrel/pawn/lua and more
A powerful C++ class library for image manipulation
automata editor
Open Source CAD