def angularExtentsOverlap(a1, a2, b1, b2):
  """
  Determine if 2 angular intervals overlap.

  a1, a2: The start and end angles definining interval a
  b1, b2: The start and end angles definining interval b
  """
  if a1 < b1:
    return (a2 >= b1)
  else:
    return (a1 <= b2)