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Circuit Builder gives you a power source, a set of bulbs and a board to route wire across. Every bulb has to end up connected, and the board rarely lets you do it the obvious way. It is a pathfinding puzzle with a constraint: wires cannot cross themselves, so the order you commit to routes decides whether the last bulb is reachable at all.
Look at the board — power source, bulbs and blocked cells.
Drag to draw wire from the source through empty cells.
Every bulb must be connected for the level to complete.
Wires cannot cross, so a bad early route can strand a bulb.
Clear a level to load a larger board.
Forward planning under constraint — thinking several moves ahead rather than taking the locally obvious step. This is the same reasoning that makes route planning and scheduling feel easy or hard, and it improves with deliberate practice on puzzles like this.
Solve the most isolated bulb first. The ones with only one approach dictate everything else.
Count free cells before you commit. If a corner has fewer routes in than bulbs behind it, that corner fails.
Hug the edges. Wires down the middle cut the board in two and strand whatever is on the wrong side.
When stuck, undo back to the last branch rather than patching around a bad route.
Yes — every board is generated from a known working layout, so a solution always exists.
No. That restriction is what makes the puzzle a planning problem rather than a drawing exercise.
No. The power-and-bulbs theme is a wrapper around a pathfinding puzzle; no circuit theory is involved.
Work out the routes in your head before drawing anything. Drawing first and adjusting is what runs you out of space.