Brain Out 2 Level 129
📝 Walkthrough
Overview
Level 129 asks "How do light bulbs light up?" In a room, a hamster-style exercise wheel is wired to an unlit light bulb on a shelf, like a small generator. A wedge of cheese sits on the lower shelf, a laptop sits beside it, and a mouse hole is cut into the wall. The victory line, "There is no such thing as free cheese!", reveals that a mouse running the wheel is the power source.
- Difficulty: Regular
- Estimated moves: 1
Step-by-Step Solution
- Look at the setup. The light bulb is wired to the exercise wheel, but no power is being generated and the bulb stays dark.
- Notice the cheese and the mouse hole. A wedge of cheese sits on the shelf, and a mouse hole is on the wall nearby.
- Move the cheese to lure the mouse. Place the cheese where the mouse can see it / at the end of the wheel.
- The mouse runs the wheel. The mouse comes out of its hole and runs inside the exercise wheel to chase the cheese.
- The bulb lights. The spinning wheel generates electricity and the bulb glows yellow. The screen says "There is no such thing as free cheese!" and the level is cleared.
Strategy & Reasoning
This is a cause-and-effect energy puzzle. The bulb is connected to a generator wheel, but nothing is turning it. The clue is the cheese and the mouse hole: mice love cheese, and the wheel is sized for a mouse to run inside.
By moving the cheese to lure the mouse, you get it running inside the wheel. The mouse's effort spins the generator, which lights the bulb. The caption's joke — "no such thing as free cheese" — means the mouse has to work (run) for its cheese, and that labor is what powers the light.
The laptop and wall switch are distractions. The lesson is to use the mouse's motivation (cheese) to turn the generator.
Tips & Common Mistakes
- Mistake: flipping the wall switch. There is no real electricity; the switch does nothing.
- Mistake: ignoring the mouse hole. The hidden mouse is the engine.
- Mistake: leaving the cheese on the shelf. Move the cheese to bait the mouse into the exercise wheel. Once the mouse runs, the bulb lights up.
Walkthrough Notes
The bulb is wired to an exercise wheel, but nothing turns it. The empty bowl of the mouse feeder and the mouse hole are the clues. Move the cheese to the mouse so it runs inside the wheel to chase it; the wheel generates power and the bulb lights. The victory line "There is no such thing as free cheese!" confirms it. Compare this with flipping the wall switch: there is no real electricity. The running mouse is the generator.
Why It Works
The exercise wheel is wired like a generator, but a wheel with nothing in it produces no current. The mouse hole and the empty food dish are the setup. Move the cheese to bait the mouse into the wheel; as it runs to chase the food, the wheel spins and generates electricity. The wall switch is a decoy because there is no mains power. The running mouse is the power plant. The caption about no free cheese ties the mouse's labor to the light.
Key Frames
