But that fact was not hard to deduce. Now standing in the street on Grimmauld Place, Albus sensed magic nearby; but since the source of that magic was under Fidelius, Albus could not point to the source. The townhouses on Grimmauld Place were numbered, from 1 to 15—except the numbering skipped 12 and went from 11 to 13. Each of the townhouses that Albus could see was sixty feet wide, with a door that was in the middle of the street side, after someone had climbed three steps to reach that door. Whilst Albus no longer could remember climbing up three steps, then knocking on a door, logic dictated that this was what he had done from the time he had cast the Fidelius on Sirius’s home until the time that the Fidelius Charm had been cast again.