▁a ▁given ▁area ▁for ▁a ▁given ▁st itch ▁pattern . ▁ ▁Th icker ▁y ar ns ▁generally ▁require ▁th icker ▁kn itting ▁need les , ▁whereas ▁th inner ▁y ar ns ▁may ▁be ▁kn it ▁with ▁thick ▁or ▁thin ▁need les . ▁ ▁Hence , ▁th icker ▁y ar ns ▁generally ▁require ▁fewer ▁st itch es , ▁and ▁therefore ▁less ▁time , ▁to ▁kn it ▁up ▁a ▁given ▁gar ment . ▁ ▁Pattern s ▁and ▁mot ifs ▁are ▁co ar ser ▁with ▁th icker ▁y ar ns ; ▁th icker ▁y ar ns ▁produce ▁bold ▁visual ▁effects , ▁whereas ▁th inner ▁y ar ns ▁are ▁best ▁for ▁ref ined ▁patterns . ▁ ▁Y ar ns ▁are ▁grouped ▁by ▁thick ness ▁into ▁six ▁categories : ▁super f ine , ▁fine , ▁light , ▁medium , ▁bul ky ▁and ▁super bul ky ; ▁quant it atively , ▁thick ness ▁is ▁measured ▁by ▁the ▁number ▁of ▁wra ps ▁per ▁in ch ▁( W PI ). ▁ ▁The ▁related ▁weight ▁per ▁unit ▁length ▁ ▁is ▁usually ▁measured ▁in ▁tex ▁or ▁dernier . ▁ ▁In ▁addition ▁to ▁choosing ▁the ▁correct ▁thick ness ▁for ▁the ▁gauge , ▁the ▁kn itter ▁must ▁also ▁pick ▁the ▁type ▁of ▁y arn ▁fi ber . ▁There ▁are ▁currently ▁about ▁fifteen ▁types ▁of ▁y arn ▁fi ber , ▁falling ▁into ▁two ▁categories , ▁natural ▁and ▁synth etic . ▁Natural ▁fib ers ▁are ▁those ▁that ▁are ▁obtained ▁from ▁a ▁plant ▁or ▁an ▁animal ▁and ▁have ▁different ▁attributes ▁depending ▁on ▁the ▁animal / plant ▁they ▁are