Mass is changing & Shapeshifting in many forms watch :-

To give a easy e.g. mini robots.

Cross-fertilisation between the emerging technological discipline of control theory or cybernetics and the new general system theory has led to characterising a systemís structure in terms of positive or negative feedback loops, responsible for the often counter-intuitive and non-linear behaviourof complex systems. Formalisation of these feedback loops as integro- differential equations has led to mathematical models of systems and to their analysis in terms of state space, phase space & attractors.