Returning multiple values from a sub.

One of the new features of version 6.90 is: "Subs parameters can be passed by reference (ByRef). This can be used to return several values from a sub"
I cannot find any documentation about returning multiple values. the only reference I found is: http://www.b4x.com/forum/questions-help-needed/5273-sub-value-return.html that does not helping much.

Thanks in advance.
David.

For example, this sub returns the two square roots of a number:

Clear example.
Thank you Erel.

David.