Thanks for reply. I try to repeat your examle, never use "Pick . . ." before.
What I see: you pick everytime only one rock. I change it to "pick all" and in your example it works well, but in mine isn't. I try to make visible rocks execute event all together. Is it possible? (why is it works in your example, but not in mine?)
Right now I can get it work only with "random pick" and every tick, but it look more like cheat.
And one more: you toggle boolean on destroing splash, but it doesn't allow to make couple of splashes at the same time (plus, I kill them with fade). It's not what I trying to test. But I can't realize: is boolean variable THAT needed? Why it can't just check visibility and work on timer?
I really want to understand principle.
Thanks again for help