The Wild Machine Slot by Pragmatic Play

Most of the time this plays like a standard 40-payline slot on a 5x5 grid. Brass pipes, electricity crackling through a glass column, and an eccentric professor with a golden mechanical arm standing beside the reels. Card suits rendered in metallic steampunk finishes fill the low end of the paytable, while painted portraits, leather-bound books with gears, purple potions, and brass instruments handle the premiums. Then the machine fires.

On any base game spin the grid can shift from 5x5 into a diamond shape - 1 position on reel 1, then 3, 5, 7, 5, 3, 1 across seven columns. When this happens, reels 1, 4, and 7 fill entirely with wilds. Paylines stretch to seven symbols long instead of five, and the wild symbol pays 3,500 coins for a full line of seven. This transformation also triggers randomly, so there's no scatter or special symbol needed to see it. The same diamond layout is permanent during Diamond Forge free spins, one of two bonus modes unlocked through the Wonder Wheel.

Three scatters on the middle reels spin the Wonder Wheel, a 30-segment wheel that awards up to five prizes per trigger - cash amounts, free spins, or both. If it lands on spins, you pick between Gold Foundry (8 spins on the regular 5x5 grid with 2-5 reels going fully wild each spin) or Diamond Forge (5 spins on the diamond grid where every wild that lands stays locked until the round ends). Gold Foundry gives more spins with random expanding wilds, Diamond Forge gives fewer spins but builds a progressively wild-covered board. Neither mode retriggers. The Wonder Wheel itself hits fairly often, but it has a habit of dropping cash prizes instead of free spins, which is the main frustration with the game's bonus structure.