Sky Foundry

5 reels × 3 rows, 243 ways, left to right. Winning symbols clear and new ones fall in; in the base game each cascade in a spin climbs 1× → 2× → 3×. Wilds land on the three middle reels.

In free spins the ladder is replaced by one multiplier for the whole feature: it starts at 1×, rises by 1 after every cascade that pays, keeps its value from one free spin to the next, and stops rising at 30×. A feature of 15 free spins ends at about 9.4× on average.

3, 4 or 5 scatters on the first drop of a spin award 15, 20 or 25 free spins; 3, 4 or 5 on a free spin add that many again, up to 60 free spins in all. The feature can be bought for 52.07× the bet with 15 free spins, for 86.88× with 20, or for 130.22× with 25. Each price is what those spins return on average, less the house's share: no tier is a better buy than another.

Bought, the three return 96.19%, 96.20% and 96.20%, as measured (each give or take 0.19 points at most); most buys return less than they cost.

When two scatters are in view, the reels still turning stop more slowly. That is decided only by the reels that have already stopped and happens every time two are in view, whether a third comes or not: it says nothing about what the turning reels will show.

One spin, feature included, pays at most 10,000× the bet: a spin that reaches it stops there and is paid exactly that.

The return printed here was measured, not derived: 96.08%, give or take 0.15 points, over 60 million spins. 38.4% of spins pay something; the free spins come about one spin in 260 and pay 21% of the return.