Re baetsi ba litsebi ba kholo ka ho fetisisa ba China le feme ea metjhini e tšoaeang mebila ea convex e ikemetseng.Ho ea ka lintlha tsa lipalo-palo tsa linyeoe tsa machaba, likotsi tsa sephethephethe li tla fokotseha ka ho feta 30% ka mor'a hore melapo ea convex e amoheloe, likotsi le tahlehelo ea moruo li fokotsehile haholo.Ka lebaka leo litsebi li ipiletsa tšebelisong ea mofuta ona oa li-mark line e le mokhoa o tloaelehileng oa polokeho ea sephethephethe.