Fur trade marten furs could generate in international markets spurred a "fur fever" in which many Russians moved to Siberia as independent trappers. From 1585 to 1680, tens of thousands of sable and other valuable pelts were obtained in Siberia each year. The primary way for the Muscovite state to obtain furs was by exacting a fur tribute from the Siberian natives, called a "yasak". "Yasak" was usually a fixed number of sable pelts which every male tribe member who was at least fifteen years old had to supply to Russian officials. Officials enforced "yasak" through coercion and by taking hostages, usually
PC Paintbrush competitor, Mouse Systems, bundled their mice with Mouse Systems' "PCPaint" in 1984. At Christmas 1984, amidst record sales volumes in the home computer market, Microsoft had created a "sidecar" bundle for the PCjr, complete with their mouse, but with their competitor's product, "PCPaint". With the release of Paintbrush the following year, Microsoft no longer needed to sell the software of their competitor in the PC mouse hardware market in order to have the same market advantage. Microsoft's mechanical mice outsold Mouse Systems' optical mice after a few years, but "PCPaint" outsold Paintbrush until the late 1980s. Unlike most other applications