Every night, I get these strange, perfectly-tempo'd knocks on the door, and no one is there when I open it. I started leaving notes, and now it's just ignoring them.

Every night, I get these strange, perfectly-tempo'd knocks on the door, and no one is there when I open it. I started leaving notes, and now it's just ignoring them.<br><br>EDIT: Well this blew up. I'll answer questions here. I'll try my best to remember exactly what I said, but I'm going to paraphrase a bit for the sake of clarity.<br><br>Q: Why didn't you record it?<br><br>A: I didn't have a voice recorder handy. Also, I didn't really think there was anything to record. I only caught on that it was a rhythm when I read it back to myself out loud a few days ago.<br><br>Q: Does it sound like your neighbors coming up the hall? Or someone knocking on a nearby door?<br><br>A: Kind of, but not really. Like I said, it's very rhythmic. It doesn't sound like any one I know, and I have no neighbors on one side (my only neighbors are above and across from me). Also, this is around 4 in the morning, when even the most rowdy members of the building are sawing logs.<br><br>Q: Why didn't you check the camera footage?<br><br>A: We don't have any. I'm in an old building and the landlord doesn't really give a shit about the tenants.<br><br>Q: Why didn't you check the shared patio?<br><br>A: The patio isn't connected to my apartment. It's connected to the floor in general, and anyone on the floor has access to it. Still, I went outside and checked last night, and I didn't see anyone.<br><br>Q: Has it happened again?<br><br>A: Yes.