Examples: the use as weapon of the rattlesnake's rattle and of the "Chinese drop" It is important to observe two parameters: the length of the sequence and the repetition interval. The musical piece called "Bolero" by Maurice Ravel contains a sequence, which is long enough to produce no irritation. In fact, every time when the sequence is repeated, there are other musical instruments. In this way, this musical piece is not too close to the irritation limit. Even so, at the end of the piece, the repeated sequence ends, producing an instant relaxation. Let's see this problem in the case of visual arts. Let's suppose a large white surface. Such a surface can produce irritation, because in any point of this surface, the IR is identical with the prediction. There is a natural tendency to put some elements on that surface, to reduce the irritation. But, if the details are randomly spread, the prediction will be different of the IR in most of the points. This also can produce some irritation. The solution found in about all cultural zones and times was to have some sequence made of identical elements, but every element has to be complicated enough so that sometimes the IR is identical with the prediction, and sometimes not. When such a surface is explored, the brain seems to have a pleasure. The pleasure can be defined as a situation when the prediction is close to IR, but about never the same. This can be seen mainly on cultural products of ancient cultures, but also nowadays. We can see this also on the shape of the Christian cross: a Christian-Orthodox cross has more detail than a Christian-Catholic cross because the Orthodox religion is mostly oriented to image models while the Catholic religion is more oriented to symbolic models. The modern cultural zones are based mainly on symbolic models. There is a reduced tendency to see all the details in a symbolic environment. Thus a perfectly plane surface, without details, will produce no irritation. This is so because, in a symbolic environment, the interaction based on image models is not important anymore. 11b. The lack of stability of the structure of models could occur when the external reality is unchanging for a very long time. Here, the prediction is also identical with IR, but there is an additional technological feature, which will be described below. As we know from the main theory, any active model will predict in a continuous automatic way the possible evolution of the external reality (this is a basic hardware feature). Now, the problem is how often this prediction is made. My supposition is that the speed of this activity is variable, and depends on the speed of changing of the external reality. That is, when the external reality is changing very fast, the new predictions are made also very often.