An attempt has been made to explain some observed evolutional characteristics of the sunspot groups by the convective model of supergranular motion. Although since the first telescopic of sunspots has past more than three and half century, we still do not have the complete theory of sunspot to include all observed phenomena. The situation is even more complicated when we search for a theory of the sunset evolution or development of sunspot groups. There are many reasons for a such situation. One of them is lack of good, reliable series of sunspot pictures with a high resolutions (better than 1,5), to cover the whole life of sunspot groups. As a matter of fact, we do not have any information from the depth of sunset formation. This is why in some cases of observations and existing theory are in contradiction. In this paper we should like to emphasize two results from contribution Bumba et al (1973), and to display present basic ideas for a possible theory of sunspot, having in mind papers: Wilson (1968), Weart (1970) and Kubičela (1973).