How to play Daily Interlock

Daily Interlock is a word-fitting puzzle. Every day you're given eight four-letter words — four marked across and four marked down — plus an empty 12×12 grid. Your job is to drop all eight words onto the grid so they interlock at single shared letters, the way entries in a crossword cross each other. When every word is connected to at least one other through a matching letter, the puzzle is solved.

The two hard rules

First: every word has to overlap at least one other word by sharing a letter — once, or more than once if the letters cooperate. A word that sits on the grid without crossing anything is illegal, even if it fits. Overlaps happen only where one word is horizontal and the other is vertical, on the single cell they share. So SWAP (across) and ANY (down) can cross on the A they share.

Second: words can't sit adjacent to each other. Two words may only ever touch by overlapping at a shared letter. If a word would end up running right alongside another word — directly above, below, beside, or bumped up against its endpoint — the drop is rejected, because those stray neighbouring letters would read as an unintended extra word. The only legal way two words meet is at a crossing.

Placing a word

There are two ways to put a word on the board:

• Drag it. Grab a word tile from the bank and drop it on a grid cell — that cell becomes the word's first letter. While you drag, the cells underneath light up green when the drop is legal and red when it isn't, so you never have to guess.
• Tap it. Tap a word to select it, then tap a grid cell to place it there. This is the mobile-friendly path, and it validates the landing position just like the drag does.

Across words extend to the right of the cell you drop them on. Down words extend downward. If the full word wouldn't fit inside the grid, the drop is rejected.

Taking a word back

Made a mistake? Grab any cell that uniquely belongs to one word and drag it — either back off the grid (to return the word to the bank) or to a different cell (to move the whole word there). You can also tap any unique cell to send that word back to the bank.

Cells at a crossing — where an across word and a down word share a letter — are deliberately not grabbable. Two words meet there, so there's no unambiguous way to say which one you meant to pick up. Grab one of the word's other cells instead.

When the puzzle solves

You don't press a submit button. The moment all eight words are on the grid and every word is tied into the network through at least one crossing, the puzzle auto-completes. “Tied in” means one connected shape — stray islands (a pair of words crossing each other off on one side of the board, while the other six interlock elsewhere) don't count. Keep connecting until the whole thing is a single lattice.

Why the grid is bigger than you need

The 12×12 grid is oversized on purpose. Eight 4-letter words don't need that much room, which means the puzzle has many different valid layouts — you can anchor the first word anywhere and build outward in whichever direction feels natural. There's no “right” position for word #1; what matters is that the eight words end up connected.

Ready for the deeper moves? Our next post digs into the habits that turn Interlock from trial-and-error into a calm, methodical solve — see Interlock strategies.