Feem ntau tsawg kawg yog 3 lub khawm yuav tsum tau haum ntawm lub qhov rooj. Lub teeb yuag sab hauv lub qhov rooj hauv tsev yuav haum nrog tsuas yog 2 hinges. Qhov rooj nrog kev ruaj ntseg ua haujlwm yuav tsum muaj tsawg kawg yog 3 khawm, vim qhov no ua rau lawv nyuaj rau kev quab yuam. Cov kev cai tua hluav taws yuav tsum tau siv lub qhov rooj hluav taws kom haum nrog 3 hinges (uas yuav tsum yog 4 nti hluav taws pov thawj pob ntseg). Rau qhov rooj tshaj 2200 hli siab, ces plaub lub hinges tuaj yeem siv los tiv thaiv kev ua rog. Xav txog lwm yam kev thauj khoom uas nce lub tshuab khawm thiab lawv cov qhov rooj dav dav, ntau theem ntawm kev tsim txom, piv txwv li tsev kawm lossis tsev kho mob lossis tsev kho mob.
Yog tias koj xav paub ntau ntxiv txog peb cov khoom lag luam hluav taws rooj tua hluav taws
