Wikipedia
Scicos
Scicos is a graphical dynamical system modeler and simulator. Users can create block diagrams to model and simulate the dynamics of hybrid dynamical systems (both continuous and discrete time) and compile these models into executable code. Applications include signal processing, systems control, queuing systems, and the study of physical and biological systems.
Scilab includes a toolbox called Xcos which is based on Scicos.
Scicos is developed in and distributed with the scientific software package ScicosLab. Scicos 4.4.1 has been released in April 2011.
The book Modeling and Simulation in Scilab/Scicos with Scicoslab 4.4 by Campbell, Chancelier and Nikoukhah, provides an overview of the software.