Whenever a spin pays nothing yet has a wild or two in view, every wild is tethered to its cell and the remaining cells spin one more time.
Wilds tied down for a second go
Tethered Wilds islands refuse to let an empty spin simply end. The server marks where each wild came to rest, pins it there and gives all the other cells a single fresh spin.
That extra spin may build lines around the pinned wilds, and any scatters it brings still go towards starting free spins. Spins that have already paid are left alone, the tether is used at most once per round, and it does not apply during free spins.
Worked example. A spin with a wild in the centre of reel three pays nothing. The wild stays put while the other fourteen cells spin again, and matching symbols landing on reels one and two of any line through that wild would now complete it.
