Liyini iKeystone?
Itshe eliyisihluthulelo liyisiqephu esiphezulu se-arch. Liyingxenye ebalulekile yompheme ngoba livimbela amanye amatshe ukuba angawi. Itshe eliyisihluthulelo lifana ne-trapezoid, ingxenye yalo ebanzi phezulu, ukuze lingasheleli ngaphandle kwe-arch. Abantu baye bakha izakhiwo eziphawulekayo ezinophahla oluqinile oluphonswe phezu kwetshe eliyinhloko. Abaklami abaningi nabanobuciko baye baziwa ngokumba izimpawu zomkhaya, izimpawu nemiklamo ematsheni abalulekile.