
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
The problem involves a cardboard disc with a smaller concentric circle divided into eight equal sectors: four white and four black. The remaining ring is divided into 10 equal sectors, alternating between five white and five black. When the disc is spun rapidly on a nail, at first the sectors blend into a uniform gray color, but after a minute, the ring appears to rotate in one direction while the disc rotates in the opposite direction, even though the entire disc is a single piece of cardboard.

This toy functions only under electric lighting, but not in every city. Why?

Present the answer in LaTex format: \boxed{Your answer}
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