A flame that reaches another bomb sets it off: its fuse becomes 1, so it explodes on the next frame, and the arm
stops. Bombs set each other off one after another: a chain reaction.
```js
// A cross of flames, `power` tiles each way. Walls stop it; a crate burns and stops it; another bomb goes off too.
function explode(bomb) {
const other = bombAt(r, c)
if (other) {
other.fuse = 1 // a chain reaction: it goes off next frame
break
}
```
What it means
bombAt(r, c) finds a bomb on the burning tile, or undefined; if (other) is true only when there is one.
Setting its fuse to 1 makes the next frame's countdown explode it, which may in turn reach another bomb.
Your turn
In explode, under the crate's if block (inside the inner loop), write the other lines.