How to solve a Fill the Space room
4-minute read
Every room in Fill the Space makes the same promise: the pieces in the tray fill it exactly, with nothing left over and nothing missing. Pieces don’t turn, so each one can only sit in a handful of places. That makes solving less about luck and more about one habit: find the spot where the choice is smallest, make that choice, and repeat.
Here’s the habit at work on a real room: room 3 from Fill the Space #2, played on September 24, 2026. It’s a 28-cell room with a notch cut out of the top edge, and five pieces in the tray.
Look before you drag
Before touching anything, add up the tray. Eight, seven, six, four and three make 28, the size of the room. That’s always true, but doing the sum makes you look at each piece. The big ones matter most: an eight-cell piece fits in far fewer places than a three-cell one, so the big pieces usually decide the room.
Then look at the room’s awkward spots. Corners are awkward because a piece has to reach into them without spilling over an edge. The cells beside the notch are awkward for the same reason. Awkward spots are where the choices are smallest.
Step 1: the top-left corner
Go through the tray piece by piece and ask whether it could cover the top-left corner. Only two can: the tall eight-cell bracket, standing along the left edge, and the straight three, standing upright in the corner. Every other piece would poke out of the room or into the notch.
Two options is a good place to think. Try the straight three in your head. It fills the top of the left edge, and the cell beside it, the last cell before the notch, is now walled in on three sides. The only way in is from below, and nothing left in the tray can reach it. One wrong guess and the room can’t be finished.
So the tall bracket goes in, down the whole left edge. That one deduction placed eight of the room’s 28 cells.
Step 2: the pocket
The bracket is open on its right side, and its arms leave a two-cell pocket between them. A pocket is an awkward spot too, so look there next. Only two pieces can reach into it: the T and the six-cell zigzag.
Try the T. Lying flat along the top of the pocket, with its bump pointing up, it covers the upper pocket cell, but the lower one is then closed in on three sides and nothing left can fill it. The zigzag, though, fills both pocket cells with its lower-left end and leans up and to the right. That’s the move.
Steps 3 and 4: the rest falls into place
With two pieces down, the room is smaller and the awkward spots are easier to see. Look at the bottom row, just right of the bracket’s foot. Only the T can cover that cell now: flat along the floor, with its bump pointing up beside the zigzag.
That leaves ten cells: a crooked strip up the right side and the corner beside the notch. The seven-cell piece is the only one that can cover the cell next to the zigzag, and once it’s in, the straight three slides into the last column. Done, with five drops for five pieces: a Perfect room.
The habit, in short
- Add up the tray and notice the big pieces.
- Find the tightest cell: a corner, a notch, a pocket, anywhere few pieces can reach.
- Try each option in your head, and look for a cell it walls off.
- Place the one that survives, then look again. The room is smaller now, and the next tight cell is easier to find.
Not every room is this strict. Some have two or three ways to fill them, and the early choices are freer. But the habit still works, because it stops you dropping a piece where it can’t stay. Every extra drop costs points, so a minute of looking is worth more than a quick guess.
Next guide: Start with the corners and dead ends