PAR for multiline machines

[luckydog]

Recently get into the slot machines, really interested in it.  Lots of questions.

1) What is the line limitation for reel based slots?   

2) If you have 3 lines for example, how do you calculate the PAR table?   The results among the three lines are not independent anymore?

    Does that mean multiple slots are all video slots?

    How do you even handle 5 lines, 9 lines or 15 lines?

[luckydog]

Hello, everyone.   Anybody help to point me to the right direction?

What is the math behind three line reel slots?     I can understand the single line machine by calculating the probability of each winning combinations.
But how do you do the same math easily for the three lines within real reels?  If you have real reels, the symbols has to be the same sequence all the times,
That makes the order of symbol important.   That's very different compare to the single line.   How do you decide the order of symbol in physical reel?

I am lost in math in calculate the probabilities.

Thanks again.