anchor.diff:          }
           if (curr_usemtl != null) {
             currObj.usemtl = curr_usemtl;
  -        }        
  +        }
         }
   
         if (line.startsWith('o ') || line.startsWith('g ')) {
  
positive.code:       print("OBJ: unknown pattern at line=$lineNum from url=$url: [$line]");
      }
  
      List<String> lines = str.split('\n');
  
      lines.forEach((line) => parseLine(line));
  
  
negative.code: 
    Part(this.name, this.indexFirst);
  }
  
  RegExp _BLANK = new RegExp(r"\s+");
  
  class Obj {
  
  