Clerver but completely unreadable.

I am aware, but I just added that to illustrate that at the very least nesting ternary statements is a bad idea for readability.

this isn't php..

I think that that is the most complicated way of getting an array from a integer I have seen

You need a an array or a string to use a for loop or I'm not understanding what you are implying.

This is quite readable, if it was a more complicated problem/solution than this approach would be undesirable.

I had exactly this! and I thought I was being very clever! :)

Nice/Clever and readable (would have minded a { or } though). I couldn't help thinking I needed to count down from something...very annoying

Because the ball drops past the window and then bounces up and passes the window again.

The rebounce = -1 is really clever!

I like this solution, it is concise and easy to read

Thanks,i like clever code,this is just for fun in the end!

Just be sure to never use anything like this in production code, certainly if you expect other people to be able to maintain it.