Hey that's interesting, Ecci Homo. Accidental manifestation... I sort of discovered the same thing in the last few weeks. I'm currently staying in Tokyo and I noticed that, during my wanderings through various parts of this immensely huge town, putting forth an intention influenced what I would encounter. I recall two of these experiences, that made me aware of this. These are a bit personal though, so I'm not sharing these, but I can say that there was no meditation or anything involved. Just thinking like 'right now I would like to experience ...' or 'tonight I would like to experience something that will teach me something and will help me develop as a human being'.
So anyway, yesterday on the subway I was standing since there was no seat available, and suddenly I thought: it is my intention that a seat will become available so I can sit, since I feel a little ill. Just when I finished this thought, the train stopped and the guy sitting right in front of me got off. Polite as I am I first waited to see if anyone else needed the seat badly, but noone made a move, so I sat down. Something like this happened before. It's fun, experimenting with this, in both 'big' and 'small' things
