,         Pair inputs
 ;+       Append sum
   ;a     Append absolute diff
     6e   Is 6 an element of this list?

 0 1
 1 1
 2 1
 3 0
 4 0
 5 0
 6 0
 7 1
 8 1
 9 1
10 1

def cheb_to_p(r, s):
    assert 0 <= s < 1

    s %= 1/8
    s *= 8 * r
    if s < 1/8:
        return (r, s)
    elif s < 2/8:
        return (r-s, r)
    elif s < 3/8:
        return (-s, r)
    elif s < 4/8:
        return (-r, r-s)
    elif s < 5/8:
        return (-r, -s)
    elif s < 6/8:
        return (-r+s, -r)
    elif s < 7/8:
        return (s, -r)
    else:
        return (r, -r+s)

def cheb_to_p(r, s):
    assert 0 <= s < 1

    sr = (s % (1/8)) * 8 * r
    return {0: (r, sr)
            1: (r-sr, r)
            2: (-sr, r)
            3: (-r, r-sr)
            4: (-r, -sr)
            5: (-r+sr, -r)
            6: (sr, -r)
            7: (r, -r+sr)}[int(8*s)]

xr = [1,1,0,-1,-1,-1,0,1]
yr = [0,1,1,1,0,-1,-1,-1]
xs = [0,-1,-1,0,0,1,1,0]
ys = [1,0,0,-1,-1,0,0,1]
def cheb_to_p(r, s):
    assert 0 <= s < 1
    sr = (s % (1/8)) * 8 * r
    i = int(8*s)
    return (xr[i]*r+xs[i]*sr, yr[i]*r+yr[i]*sr)

  Polygon middle = new Polygon(
    { 2, 2.5, 2, 1.5 },
    { 1.5, 2, 2.5, 2 },
    4
  );

quadrant = int((degrees(atan2(y, x)) % 360) / 45)

    int operator[](int index) {
      while (results.size() <= index) {
        result = setjmp(me);

        if (result == 0) {
          longjmp(*generator);
        }

        results.push_back(result);
      }

      return results[index];
    }