Block Blast Planner

A move planner for Block Blast, the 8×8 block puzzle game. Tap in what's on your board, pick the three pieces you were dealt, and it shows the best order and position for each one: which lines it clears, how combos chain, and how the board looks after your turn.

Live: https://blast.k1mochi.cloud

Features

• Tap-to-paint board. Tap a cell to fill it, or drag to paint several at once. Works with mouse, touch and keyboard.
• Piece picker. A library of the game's shapes (lines, squares, corners, L, T, S/Z), or draw any custom shape in a 5×5 grid.
• Full search. Every order of the three pieces and every legal position is tried, with row and column clears applied after each placement, just like the game.
• Step-by-step plan. Each move gets its own mini board showing where the piece goes, the exact rows and columns, and the lines it clears. Combo chains are labelled.
• Backup plan. A second-best plan that starts with a different move.
• Board risk check. Rates the board low, medium or high risk, and warns about single-cell gaps and missing room for 3×3 blocks or 1×5 lines.
• Deadlock warning. If the three pieces can't all fit, it tells you which piece is stuck and shows the order that places the most.
• Turn loop. "I played this" sets the board to the result so you can enter your next three pieces.
• Remembers your board. Your board and pieces are saved in the browser.

How the planner picks a move

Block Blast doesn't publish its scoring formula, so the planner ranks plans with a heuristic instead of a points estimate:

Factor	Effect
Lines cleared	Biggest reward. Clearing several lines with one piece earns a bonus.
Clears in a row	Each clearing move after the first in the same turn earns extra, which keeps combos going.
Ending on a clear	Small bonus, because the streak carries into your next turn.
Open space	More empty cells is better.
Fragmentation	Ragged edges between filled and empty cells are penalized.
Single-cell gaps	Heavily penalized; only a 1×1 piece or a clear can fill them.
Room for big pieces	Bonus if a 3×3 block, a horizontal 1×5 and a vertical 1×5 still fit.

The search uses bitmasks (one byte per row), so a full turn of three pieces runs in a fraction of a second in the browser.

Run it

It's a single static file, public/index.html, with no build step or dependencies.

Locally

cd public
python -m http.server 8080

Then open http://localhost:8080, or just open public/index.html directly in a browser.

With Docker

docker compose up -d

This serves the page with nginx on port 8092. The compose file also joins an external Docker network named edge, which a Cloudflare Tunnel container uses to reach the site. If you don't have that network, either create it with docker network create edge or remove the networks sections from compose.yaml.

Edits to public/index.html appear on refresh. No container restart is needed.

Project layout

public/index.html   the whole app: markup, styles and solver
compose.yaml        nginx container for self-hosting

License

MIT