with the search "shuffling an array" you could have found this: How do I shuffle an array randomly?

Nevertheless, regarding your code, I think there is a problem:

$x = $x > 0 ? $x - 1 : $x;
[download]

This will make the chance for a 0 double the chance of any other number.

I wouldn't use splice. I'd go te way of really shuffling the array and then printing it either complete or using the elements in sequence one by one.

For shuffling seethe link I gave above.