Every wild that lands stays locked for the rest of the round. Press Run a few times — watch the board fill up.

Where a walking wild migrates, a sticky wild just… stays. Great for free-spin bonus rounds — each new wild locks in place, building up through the round until board fills feel inevitable.

interface StuckWild { reel: number; row: number; symbolId: string }
const stuck: StuckWild[] = [];

async function playFreeSpin() {
  const promise = reelSet.spin();

  // Build the grid: server's random result, but overwrite with stuck wilds
  const grid = (await serverSpin()).symbols;
  for (const w of stuck) {
    grid[w.reel][w.row] = w.symbolId;
  }
  reelSet.setResult(grid);
  await promise;

  // Any NEW wild on this spin joins the sticky set
  for (let r = 0; r < grid.length; r++) {
    for (let row = 0; row < grid[r].length; row++) {
      if (grid[r][row] === 'wild' && !stuck.some(w => w.reel === r && w.row === row)) {
        stuck.push({ reel: r, row, symbolId: 'wild' });
      }
    }
  }
}

function endFreeSpinRound() {
  stuck.length = 0;
}

Optional: animate the lock-in

When a wild first lands, give it a visual “click” so the player notices it became sticky:

reelSet.events.on('spin:reelLanded', (reelIndex, symbols) => {
  for (let row = 0; row < symbols.length; row++) {
    if (symbols[row] !== 'wild') continue;
    const isNew = !stuck.some(w => w.reel === reelIndex && w.row === row);
    if (isNew) {
      const sym = reelSet.reels[reelIndex].getSymbolAt(row);
      gsap.fromTo(sym.view.scale, { x: 1.3, y: 1.3 }, { x: 1, y: 1, duration: 0.4, ease: 'back.out(2)' });
    }
  }
});

Variations

Expiring stickies — each wild has a counter; decrement every spin, unstick at zero.
Stack-up wilds — every spin stack a second “wild overlay” on existing stuck wilds (increments a multiplier or a displayed number via a slot object).
Wild gravity — stuck wilds drift downward one row per respin until they reach the bottom.

Walking wild — wild migrates instead of stays
Hold & Win — same pattern but for coin/bonus symbols

Optional: animate the lock-in

Variations

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