Biirta wareega ee hal saf ah ayaa si fiican ugu habboon inay qaadaan xoogagga radial-ka sare. Iyada oo ku xidhan naqshadda ama meelaynta garbaha, biirta wareega ee dhululubada ah waxay awood u leeyihiin inay u adkaystaan xoogagga dhidibka hoose ee hal ama labada jiho. Biirta wareega ee hal saf ah waa biirta la kala saari karo - taasoo sahlaysa in la isku xidho ama la kala furfuro biirta.
