I have some questions about phenomena, specifically for Black and White.
If you stand next to some tiles of grass, is it possible that suddenly a tile of rustling grass will appear just by time passing? Or can a tile of rustling grass only appear when you make a step, so you have to keep walking / running / cycling for the rustling grass to appear?
Similarly, does the grass stop rustling if you stand next to it for too long, or if you make to many steps?
When the rustling grass tile appears in the middle of some other grass tiles, you have to go through those first to get to the rustling one. Is there any way to avoid encountering wild Pokemon until you get to the rustling tile, and then step onto the rustling grass and encounter that Pokemon?