Ngenxa yeenzuzo zayo zemveliso yobuninzi, ulwandiso loluhlu lwesicelo lubanzi, ukusuka ekusebenziseni iglasi yeglasi yokutyibilika ukuya kwiglasi yodonga yangasemva. Kuba imilo yevili lokusila inokutshintshwa, isipili somkrolo wesithuthi sinokuvela neemilo ezininzi ezahlukeneyo zemigca.