Fire Line — free browser game

A forest fire has broken out and putting it out is beyond you — the only thing you can do is get ahead of it and contain it. The board is full of trees (green); in one corner is the blue village (4 houses) you must protect, and in the opposite corner is the orange flame. The game is turn-based: first you plan, then you let the flames spread. Each turn you have 4 'digs'; clicking a green square cuts that tree and turns it into a non-burning fire line (brown). Within the same turn you can click a line you opened in the wrong place to undo it (the dig is refunded). When you're ready, you press Space or click the 'Advance' button: the flame jumps one square at once to all of its orthogonally adjacent trees and houses. The squares framed in orange show in advance where it will jump next turn — build your line according to this warning. The flame is stopped only by a fire line, a natural clearing (grey) or the edge of the board; if you completely surround the flame with these obstacles it counts as 'contained' and the round ends. The goal is twofold: no house must burn (if a house catches fire the village burns and the game ends) and, when the game ends, as many green trees as possible must be left standing. Watch out: every line you open also costs a tree, so cutting more than necessary lowers your score too — a narrow, smart line is better than a wide one. Your score, when it's over, is the number of remaining trees; the highest is saved in your browser. R resets everything and generates a new random map. Tip: don't try to surround the flame in the open — steer it toward the edge of the board or toward natural clearings so you can close it off with a shorter line.