Huff N' Lots of Puff Slot by Light & Wonder

The frame system is what makes this one tick. Every position on the grid tracks a building material during free spins - empty, Straw, Stick, or Brick. Hard Hat symbols either stamp a new Straw frame onto wherever they land or upgrade what's already there. Straw becomes Stick, Stick becomes Brick. Land one on a position that's already Brick and it finds somewhere else to upgrade, or pays 10x if the whole grid is maxed out. When free spins end, the wolf shows up and blows. Straw houses pay 0.5x to 1.25x. Stick bumps that to 1.5x-5x with shots at Mini or Minor jackpots. Brick is the target - 5x to 180x per position, plus Mini, Minor, Major, or Grand jackpot chances.

Six Hard Hats on one spin trigger the bonus, and a toolbox assist randomly adds 1-6 extra Hard Hats to help reach that threshold. Once inside, 3 or more Hard Hats on any spin add another spin to the counter. But the bonus branches beyond just collecting frames. Wheel symbols on reels 2 and 4 either upgrade a wheel wedge or spin it outright - wedges climb from Mini through Super (7,500x). Buzz Saw symbols on reels 3 and 5 fill a separate counter that, when triggered, drags saws across the grid stamping Straw frames on every position they touch. The Mega Hat drops oversized symbols (2x2 up to 3x5) that convert covered positions to Straw before free spins begin, and its Super variant expands the grid to 5x6 first. Mansions skip the upgrade path entirely - three Hard Hats stamp Brick frames directly, no Straw or Stick in between.

This is the tenth-ish game in the Huff N' Puff franchise, and the naming has gotten harder to track than the mechanics. Huff N' More Puff, Huff N' Even More Puff, Huff N' Extra Puff, Huff N' Xtra Puff - now this. Five jackpot tiers sit on the left side of the screen (Mini at 20x up to Super at 7,500x), all scaling with your bet. The base game runs 243 ways with wilds limited to reels 2-4, which keeps things quiet between triggers. Three pig characters fill the high-pay positions - one in a suit, one in a hard hat, one holding a scepter - working the "Bacon Bros Building Co" construction site that frames the whole thing.