code: func (t *Pot) EachNeighbour(val Val, pof Pof, f func(Val, int) bool) bool {
  	return t.eachNeighbour(val, pof, f)
  }
docs: // EachNeighbour is a synchronous iterator over neighbours of any target val
  // the order of elements retrieved reflect proximity order to the target
  // TODO: add maximum proxbin to start range of iteration