Izinkomba, isimo esikhulu sesikhokhela sebhulokisi, zingamaqembu amaningi futhi zingamaqembu amakhulu ukuze zikhombise isikhokhelo sebhulokisi kanye nezinsimbi zomthwalo wemithombo. Iyinhloko yezinqubo zombili yezinsimbi nesayithiki.