Also you can lauch multiple components from the command line by typing the components you want, e.g.
user@machine ~ $ erf /usr/share/erf/about.erf.xml ground.erf.xml /usr/local/share/erf/lights.erf.xml
When we load components into an application these components are placed in the application by the order they are loaded. This can affect the rendering of the scene due to the fact that objects drawn with alpha must be drawn from far to close. So the correct order for drawing would be lights, ground, laser close to the ground, laser higher than first laser, webcam, etc.