Noocyo kala duwan ayaa la heli karaa, kuwaas oo ku habboon nidaamyada kala duwan ee shaandhaynta, sida shaandhada hoose, shaandhada dambe, shaandhada dhinaca, shaandhada sare, socodka qulqulka, shaandhada dibadda, baaldiga shaandhada iyo habab kale oo shaandhaynta ah ayaa la isticmaali karaa.