For once it might be my turn to tell something interesting that not everyone here knew before: There is a simple solution to that, using only standard switches

For once it might be my turn to tell something interesting that not everyone here knew before: There is a simple solution to that, using only standard switches and the standard power wire, -in fact I think this is a standard thing for fresh electricians-to-be to learn first year in school here. Edit: I have this setup at home in my staircase so I don't have to walk up (or down) to turn on/off he lights.