Stacked

• Tap a tile in your rack, then tap an empty square to place it — or drag a rack tile straight onto a square, including onto a tile already down to stack on it. Tap a placed tile to take it back, or drag a tile you just placed to a different square, or back onto your rack to take it back. Dropping a tile somewhere it can’t go sends it back to your rack.
• Reorder your rack: drag a rack tile left or right over the other tiles and let go — a blue bar shows the gap it will land in, and your tiles stay in that order. Drag it to the far end to move it to the end of the rack. Shuffle still mixes them at random.
• Board view: the board grows from 7×7 up to a full 15×15. Picking up or dragging a tile never zooms the board — it stays at the full view so you can see where you want to put the tile. Only once you place the tile down does the board reframe on its own around the word you’re building — it zooms in a little and centres on the whole word, with the tile you just placed in view, so the squares around it are bigger and easier to tap. If the word is long, the board stays zoomed out far enough that you can see the entire word instead of zooming in and cutting off its ends. Swipe or drag to look around while zoomed, tap + or − under the board to zoom more or less, or tap Fit whole board to see everything at once again. When your turn ends — you play a word, pass or swap — or you tap Clear to take your placed tiles back, the board zooms back out to fit the whole board on its own, ready for the next turn.
• Stacking: tap a rack tile, then tap a square that already has a tile to cover it. The top letter is the one that counts; the buried letter no longer scores. Stacked squares show a layered edge and a “2” badge. A square can hold at most 2 tiles, so a stacked square is locked — tap it with no tile selected to see what is buried underneath. Stacking earns +3 per stacked tile, but the square's bonus does not trigger a second time, the stacked letter must differ from the one underneath, and a square stacked on one turn cannot be stacked again on the very next turn.
• The board grows: every game starts 7×7 on the full 15×15 bonus layout. Any played word that touches the outer edge grows the board one full ring on all four sides (up to 15×15) and scores the player who triggered it +10 — at most one expansion per turn. The new ring opens for the next player, not on the turn that triggers it, and stacking works everywhere on the grown board.
• Daily Duel (the main game): a solo daily puzzle, Wordle-style. Everyone who plays on the same date gets the same seeded board, the same starting rack of 7 tiles and the same seeded refill bag. Every starting rack is checked before it is dealt: the seeded tiles must be able to make a word on the starting board — if they can’t, the deal is re-seeded until they can, so a Duel never starts with a rack that has no word in it. You always hold 7 tiles: after every move, the tiles you played are replaced from the refill bag, so you start each move with a full rack and fresh letters — and you have 3 moves to post your best score. A pass uses up a move (your rack is already full, so a pass draws nothing). Stacking (+3) and growing the board (+10) still count. It is once a day with no replay: when your 3 moves are done, today’s Duel is done. A countdown then runs to the next puzzle — a new Duel lands at midnight in your local time, when the board, rack and moves reset and yesterday’s puzzle locks. Copy your shareable result, keep your daily streak going, and chase the leaderboard — the top score each day takes the Daily Champion crown for 24 hours.
• Test game (when today’s Duel is over): tap Test game — play now at the top, or the big test-game button that appears when the Daily is done. You get a brand-new solo puzzle right away — 3 moves, rack always refills to 7, starting rack checked so it can make a word — and you can start another one as often as you like with New test game. Test games never change today’s Daily score, streak or crown.
• Play with friends: the full two-player Stacked game — pass the phone, refill from the bag, swap and pass as usual. The board still grows 7×7 to 15×15 and stacking works exactly the same.
• Your progress saves itself: after every move, today’s Duel and any Play with friends game in progress are saved on this device. Close the app mid-Duel and you reopen on the exact move, score, board and rack you left — a finished Duel stays finished for the day, and a friends game resumes on the right player’s turn.
• Your games (async preview, Play with friends): save up to 3 games in progress on this device, see whose turn each one is waiting on, and move a game to another device with an export/import game code. Real cross-phone play — accounts, server sync, “your turn” notifications — is a later step and is not live in this prototype.
• Your word must run in one straight line, with no gaps, and touch tiles already on the board (except the very first word, which must cover the ★ in the middle).
• Words that cross your letters count too — every word on the board has to be a real word. That includes every word running through a stacked tile: one bad cross-word rejects the whole stack.
• Colored squares boost your score, but only the first time a tile lands on them. Use all 7 rack tiles in one turn for a 50-point bonus.
• TW triples the whole word, DW doubles it, TL triples the letter, DL doubles the letter.
• In Play with friends, Swap tiles or Pass to end your turn. That game ends when the bag is empty and someone plays their last tile, or after four passes in a row. In the Daily Duel there is no swap and no leftover-tile penalty — your rack refills to 7 after every move, and your score is simply what your 3 moves earn.

Blank tiles are wild: pick any letter when you place one. They score 0 points.