The pentagonal side wheels reduce the rotation angle from 110º to 72º: A reduction of 35% of the rotation angle.
The shorter rotation angle produces a much inferior spark than a standard lighter:
• Since it has a shorter run to generate it.
• Since it has much less acceleration:
When activating the wheel, it starts turning slowly and keeps accelerating with the finger impulse, until the run finishes, at a much higher speed than the initial one.
Finishing then the shorter run at a much lower speed.
This slower speed produces as well much lesser energy (spark).
Only when the child succeeds rotating the wheel (most of times he is not able),
the strength he applies to the pentagonal wheel does not produce enough energy to ignite the lighter.