Icyuma gishyushye kizengurutswe nicyuma kirekire, gishobora kuzunguruka hamwe nu mpande enye zambukiranya intego rusange.Ibisobanuro byayo bigaragarira muri milimetero z'ubugari * ubugari, kandi ibyuma biringaniye birashobora kuba ibyuma birangiye, bikoreshwa mubice, urwego, ibiraro n'uruzitiro.