The glass, the sevens, and the spin button still look like a slot from decades ago. The machinery behind them does not. A classic cabinet once stopped because gears, springs, and a physical reel came to rest. A modern machine, and every game on Slothill, stops because software draws a number and looks up the symbol that number belongs to.
What happens when you press Spin
Press Spin on a 3-reel game and the server draws one random number for each reel. A five-reel game would draw five. Those numbers come from a fixed range built into that game. Inside the range, every number is equally likely. An 8 is no rarer than a 93.
The symbols are not equally likely. Each number is mapped to a symbol, and common symbols own more of the range than rare ones. That is why bars show up more often than a jackpot symbol. The jackpot symbol might be tied to only one or two numbers. Everything else is spread across the rest.
Here is the idea with round figures, not the odds of any Slothill game. If one number in a hundred maps to the jackpot symbol, the chance of that symbol on one reel is 1 in 100. The chance of it on all three reels is 1 in 100 × 1 in 100 × 1 in 100, or 1 in a million. Each game on this site uses its own map, so the real odds live in that game, not in this illustration.
One map, or a map per reel
Many casino machines give each reel its own map. The same drawn number can then mean a different symbol on reel one than on reel two. Slothill does the simpler thing: each free slot uses a single map for all three reels. The same number lands on the same symbol wherever it is drawn.
How the paytable finishes the spin
Once the symbols are chosen, the game scores them against the paytable printed on the machine. That table lists which sets pay and how many credits each set is worth. Rare sets pay more than common ones. A wild, where the game has one, stands in for another symbol so a line can complete. Some wilds also multiply that win. The paytable under the cabinet is the rule, not a guess from the symbols alone.
Slothill runs these games in the browser as HTML5. There is no download, and the result is chosen on the server. Credits are for play, not cash. After this guide, try Lucky Seven or Triple Diamond, then read how hit frequency differs from payback.