rresponds to the timeStep of SOFA.
	<br>
	At each step of the scheme, the linear equation systems obtained have to be solved by an auxiliary component, the CGLinearSolver, which can be of different kinds (conjugated gradient, ...).
        <br>
	<div id="orangeText">Key points</div>
	<br>
	Different simulations are proposed:
	<ul>
		<li>Green: reference deformation.</li>
		<li>Yellow: Mechanical system using springs along edges.</li>
		<li>Light blue: Mechanical system using tetrahedron finite elements.</li