In the traditional signal-flow modeling scheme, users must first make, for example, a free body diagram of a spring-massdamper system. Here, the mass resists acceleration and stores kinetic energy; the spring resists displacement and stores potential energy; and the damper resists velocity and dissipates energy. In this idealized system, it is assumed that a force F is applied to the mass so that it is displaced positively along the direction of the given axis. Several pages of derivations are required just to translate this free-body diagram to a differential equation that would let users solve for variables such as oscillation and damping effect.