Zida ziwirizi zili ndi mikhalidwe yosiyana yomwe imakhudza momwe zimagwirira ntchito, kulimba, komanso kagwiritsidwe ntchito kake. M'nkhaniyi, tikuyang'ana dziko la ma hinges, kufananiza mitundu yachitsulo ndi aluminiyamu kuti tidziwe kuti ndi zinthu ziti zomwe zimalamulira kwambiri.