Isondo
Isondo liyisigcoyi esiyindilinga esihloselwe ukundiyaza emshizeni. Isondo liyisigcoyi esibalulekile sesondo nomshiza okuyingxenye yezinguxa ezilula eziyisithupha. Amasondo, lapho ehlangane nemishiza, avumela ukuba izinto ezinzima kube lula ukuzihambisa ngokwenza ukuthi kube khona umdiki noma intutho kuyilapho aseka umthwalo, noma enza umsebenzi ezinguxeni. Amasondo afana nesondo lomkhumbi, isondo lokuqondisa, isondo lombumbi, kanye nesondo lokundiza.
Izibonelo ezivamile zesondo zitholakala kwezokuthutha. Isondo liphunguza umshikisho ngokwenza ukunyukuza lapho liqonqoloza kanye nemishiza. Ukuze isondo lindiyaze, kudingeka kube nesiphoqi esizokwenza kube nomjijayane oqombolayo. Ngokusebenzisa isondo, abase-Sumeri baqamba isilekeleli espimpilizisa ubumba lapho umbumbi elubumba kube into ayifunayo.