sclass OnePath {
  new ByteBuffer steps;
  
  static final Pt[] directions = {
    pt(0, 0),
    pt(-1, -1),
    pt(0, -1),
    pt(1, -1),
    pt(1, 0),
    pt(1, 1),
    pt(0, 1),
    pt(-1, 1),
    pt(-1, 0)
  };
  
  int size aka length() { ret steps.size(); }
  
  toString {
    ret singleDigitBytesToString(steps);
  }
  
  // includes first point, so returns length()+1 points in total
  ItIt<Pt> pointIterator(Pt startPt default origin()) {
    ret new ItIt<Pt> {
      int i = 0, n = length();
      Pt p = startPt;
      
      public bool hasNext() { ret i <= n; }
      
      public Pt next() {
        ret p;
        if (i < n) p = translatePt(p, getStepAsPt(i));
        ++i;
      }
    };
  }
  
  Pt getStepAsPt(int i) {
    ret directions[steps.get(i)];
  }
}