Footbridges

Expert Footbridges puzzles

Expert puzzles are 11×11 and 12×12 with 22 to 35 islands, and a few times in each one you'll need to think a few moves ahead: imagine fewer bridges somewhere, follow what it forces, and if an island ends up short or a group gets cut off, the bridges have to be there.

Practice gives you puzzles you haven't solved yet, as many as you like, and keeps your best time without hints. Every puzzle has exactly one solution and can be solved by logic alone.

How to play Footbridges

1. Every island's number is how many bridges it has.
2. Bridges run straight across or down, between two islands with only water between them.
3. Two islands can be joined by one bridge or two, never more.
4. Bridges can't cross each other.
5. In the end, all the islands are joined into one group.

Drag from an island toward a neighbor to build a bridge, and do it again for a second one. A third time takes them away. Tapping the water between two islands works too. An island lights up once it has all its bridges. On a keyboard, use the arrow keys to move between islands, Shift and an arrow to build that way, and Ctrl+Z to undo.

Solving tips

• Start with the big numbers. A 4 in a corner, a 6 on an edge or an 8 anywhere needs two bridges to every neighbor.
• Count what's left. A 3 with only two neighbors needs at least one bridge to each of them, and a 5 with three neighbors does too.
• Don't close a group off. Two 1s can't be joined to each other, and two 2s can't be joined by two bridges: they'd be finished, with no way left to reach the other islands.
• Keep a way out. When a group of islands has only one link left to the rest, that link needs a bridge.