A virtual reel can have thousands of stops. 99% of those can map to the same physical space. That's the magic of Telnaes.
A typical PAR sheet is mentioned in the study two leaps above, but that's just reverse-engineering the math. Understanding virtual reels helps look at it from the designer's direction.
The invention of "bonus games" that play when a certain reel combination was hit also changed the math drastically. A lot of companies that were locked out of virtual reels by IGT's ownership of the Telnaes patent used this technique to offer similar payout structures.
That's probably true I'm just going by memory and what we have.
IGT seems to own all, it's like you can't touch a thing without IGT being involved. I've even heard stories of potential new IGT employees being asked if they have any invention ideas, if they do IGT will but them.
If you're curious just search for "PAR sheet" or "payable and reel sheet".