Purpose of second argument for math.randomseed

[Lorenzo Donati <lorenzodonatibz@...>]

Hi all!

I've noticed that in the new 5.4.0-work2 release math.randomseed has got 
a new optional second argument.

Quoting the manual:

------------------------------------------------------------
math.randomseed (x [, y])

Sets x and y as the "seed" for the pseudo-random generator: equal seeds 
produce equal sequences of numbers. The default for y is zero.
------------------------------------------------------------

Does anyone knows what's the purpose of the y argument, besides making 
the seed "bidmensional".

Cheers!

-- Lorenzo