[DB112] Turn On the Light

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111 - How Many Turns?

112 - Turn On the Light

113 - A Stack of Dice

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Turn On the Light
Game	Professor Layton and the Diabolical Box
Number	112
Type	Write Answer
Location	Museum Gate
Given by	Duke
Solved by	Professor Layton
Picarats	40
Mandatory	Yes
Reward	Photo Scrap
In other languages
日本語	ライトをつけよう raito o tsukeyo u
Deutsch	Licht an!
Español	¡Luces por favor!
Français	Un trait de lumière
Italiano	Accendi la luce
한국의	전구에 불을 켜려면

Turn On the Light (Turn on the Light in the UK version) is a puzzle in Professor Layton and the Diabolical Box. The puzzle must be solved in order to progress the story.

Puzzle

US Version

The board shown on the left is wired on the underside so that holding contact points A and B together turns the light on.

Now look at the picture on the right. This light has three contact points: A, B, and C. No matter whether you hold contact points A and B, B and C, or A and C together, the light stays on. In that case, how must the wires be connected on the underside of the board? Draw the solution that requires the fewest number of connections. The dotted red line indicates a known wire.

UK Version

The board shown in the picture on the left is wired on the underside so that holding contact points A and B together turns the light on.

Now look at the board in the centre. This light has three contact points: A, B and C. No matter whether you hold contact points A and B, B and C or A and C together, the light stays on. In that case, how must the wires be connected on the underside of the board? Draw the solution that requires the fewest number of connections. The dotted red line indicates a known wire.

Hints

• →
• Hint 1
• Hint 2
• Hint 3

Click a Tab to reveal the Hint.

US Version

"No matter whether you hold contact points A and B, B and C, or A and C together, the light stays on."

This might make you think that the electricity has to run through all three of these connections, but at the same time, the positive and negative signals need to be isolated from each other, which makes things more difficult. Read the conditions you have to meet again as carefully as you can.

UK Version

"No matter whether you hold contact points A and B, B and C or A and C together, the light stays on."

This might make you think that the electricity has to run through all three of these connections, but at the same time, the positive and negative signals need to be isolated from each other, which makes things more difficult. Read the conditions you have to meet again as carefully as you can.

You might be tempted to construct something resembling a proper wiring job, but that won't do the trick here. Be flexible in your thinking about what will get the job done!

You only need to draw one wire!

Solution

Incorrect

Too bad!

Are you sure your solution meets all the conditions set out by the puzzle?

Correct

Bright idea!

US Version

All you really have to do is connect that lightbulb to the battery. The puzzle tells you that the light stays lit even when contact points A and B, A and C, or B and C touch. Naturally, the light will also stay lit even when none of those points touch.

UK Version

All you really have to do is connect that light bulb to the battery. The puzzle tells you that the light stays lit no matter which combination of contact points are held together. Naturally, the light will also stay lit when none of those connections are made.