Um... sorry, but I'm still struggling with the issue of flying objects. Essentially, it's impossible (I specify all the coordinates, but the effect either hangs in one place or doesn't play at all). I'll reveal a secret: there wasn't an arrow in the final video, but it still created the impression (here, the effect of desired-actual perception comes into play; for example, if bus number 17 is coming, but you really need bus number 19, you can easily see the number 19) :)