Cool Jewels Slot by Light & Wonder

The mechanic that defines this 2014 Williams Interactive cabinet is the Pay Per Symbol meter, a frozen thermometer that climbs the left side of the grid and decides what every destroyed symbol is worth. It starts at £0.01 per symbol and has 12 sections topping out at £0.50. Every symbol you destroy fills slices on the current section, and once you push into the next tier the new per-symbol value sticks for the rest of that game. So a slow opener that survives long enough to nudge the meter up a few rungs starts paying meaningfully more for every cluster that lands after it. The Premium symbol (the ice-clad diamond with a red 10x label) pays ten times the current meter value, so one Premium at the top section is worth £5.00 on its own. The meter resets at the end of each base game, but here is the kicker: the PPS value carries over into the Free Games Bonus. Triggering the bonus on a hot meter is a different game than triggering it cold.

Clusters are 4 or more connected matching symbols, evaluated top-to-bottom then left-to-right. Three activating wilds live on reels 2 to 5. Unstable destroys connected neighbours in a cross. Shattering wipes the rest of its row and column. Shocking takes out both diagonals. When two of these land horizontally adjacent and both activate, the next cascade arrives with a coloured residue on the affected cells: pink (Unstable + Shattering) destroys the non-wild symbols sitting on those cells after the regular match, green (Unstable + Shocking) turns those symbols into wilds for base icons, and blue (Shattering + Shocking) pays 10x the meter value for any symbol destroyed on a marked cell, or 100x if it is a Premium. Overlapping watermarks stack, so a striped cell carries both effects. Two like wilds together form a Persisting Wild that triggers an Unstable cross and slides down the reels each cascade until it falls off the bottom or stops contributing to a win.

Bonus collection runs on destroyed Bonus symbols rather than landed ones, with 4 awarding 8 free games and the count climbing through 10, 15, and 20 to a +5 per Bonus extension past 7. The bonus is guaranteed to pay at least 10x the total bet, with any shortfall topped up by a Mystery Kicker. Two ceilings to keep in mind: a hard 30-cascade cap per game, and a cash max of $250,000 regardless of stake, which translates to 500,000x at the minimum bet but only 1,250x if you push the slider all the way up. No buy bonus, no ante, no jackpot ladder. Visually it is a polished arcade gem tray set against icy peaks and snowdrifts, with the frozen meter ticking up as you play.