/**
* Updates the positions of nodes and edges in the viewer. This method does not normally need to
* be called as update happens every time draw() is called. Calling this method can be useful if
* you wish to speed up the movement of nodes and edges by updating their position more than once
* every draw cycle.
*/
public void updateParticles() {
physics.tick(0.3f); // Advance time in the physics engine.
}
