many unstable periodic solutions. 

We propose two techniques of obtaining exogenous chaotic cycles as solutions of differential equations. In the first approach, an economic model with a limit cycle is perturbed chaotically to produce a chaotic business cycle. In the second one, we consider a system with an equilibrium, perturb it by cyclic chaos and observe that a chaotic business cycle emerges as a result. While the first method is theoretically verified in [9], the second method of cyclic chaos generation is new and is demonstrated in our paper through simulations. Currently, we study cases where the shocks enter the system additively, but future investigations may involve more complex scenarios, where the disturbance enters the main functions of the economic model. 

Goodwin [41] argues that the apparent unpredictability of economic systems is due to deterministic chaos as much as to exogenous shocks. In this sense, our results can be interpreted as the transmission of unpredictability from one economic system to another, and even models that do not admit irregularity in isolation can eventually be contaminated with chaos. Thus, we provide support to the idea that unpredictability is a global phenomenon in economics, and demonstrate one of the mechanisms for this contagion. Considering the current extensive globalisation process, this is a good depiction of reality. 

Our results demonstrate that the control may become not a local (applied to an isolated model) but a global phenomenon with strong effectiveness such that control applied to a model, which is realizable easily (for example, the logistic map or Feichtinger’s generic model), can be sufficient to rule the process in all models joined with the controlled one. Another benefit of our studies is that in literature controls are applied to those systems, which are simple and low-dimensional. Control of chaos becomes difficult as the dimensions of the systems increase and the construction of Poincaré sections becomes complicated. Chaos control cannot be achieved if we do not know the period of unstable motion to be controlled. In our case, the control is applicable to models of arbitrary dimensions as long as the basic period of the generator is known. For these reasons, the possibility to control generated chaos by controlling the exogenous shocks that produce the said chaos is appealing. It is especially appealing from a policy- maker’s point of view, as it offers a cost-effective way to regulate an economic system. 

Control of chaos is nowadays a synonym to the suppression of chaos. Thus our results give another way of suppression of chaos. If we find the controllable link (member) in a chain (collection) of connected chaotic systems, then we can suppress chaos in the whole chain. This is the effective consequence of our studies. 

## 1.1 Organization of the paper 

The paper is organized in the following way. In the next section we describe the input-output mechanism that serves as the basis of chaos extension and formulate two theorems that provide theoretical support to the subsequent discussion. In Section 3 economic models with regular motions - stable equilibrium and 

