digit of their binary representation fulfills the following conditions:
* Either or
* only for finitely many indices .
* If denotes the largest index such that then
* If and then exactly one of the following two conditions holds: or Informally, these conditions means that every digit of the binary representation of that equals 1 belongs to a pair ...0110..., except for ...010... at the very end.

Now, is an explicit set consisting entirely of isolated points but has