Motions are abstractions of spendature of energy and where the energy should be spent. These is simply an address on an actor and a motor with an assigned energy strength, this energy may be positive or negative to indicate for example expansion and contraction of a motor or the torque applied to a motor clock-wise or anti-clock-wise. Its is the absolute magnitude of the strenght that counts towards total energy spendature. Motions are passed through reaction model as messages produced by the agent, this the way the external agent affect the environment.