https://www.youtube.com/watch?v=mA7xFjvaWY4

Excellent job!
You've sped up its rotation by reducing its moment of inertia when its radius is contracted much like an ice skater does while performing her routine ...

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Thus, it must be surmised that reducing its moment of inertia takes less effort than is the gain in rotary speed which is, precisely, what is experienced by an ice skater.

"The moment of inertia, also known as angular mass, second moment of mass, or rotational inertia, is a property of a rigid body that determines the torque needed for a desired angular acceleration about a rotational axis. It is the sum of the products of the mass of each particle in the body with the square of its distance from the axis of rotation. The formula for moment of inertia is I = miri2. It is important in almost all physics problems that involve mass in rotational motion and is used to calculate angular momentum and explain how rotational motion changes when the distribution of mass changes." -- Brave Search for: "moment of inertia".

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https://www.youtube.com/watch?v=f7_d4gVUQ24

Their description of alternating radii is backwards. Yet, the alternating condition of moment of inertia (serving as an equivalence for mimicking an alteration of spinning mass) is correct.

The radius of spin for each pair of white wheels is furthest from the center on each upstroke (which decreases moment of inertia and decreases its equivalent parameter of mass) making it easier to lift on the upstroke while being closest from the center on each downstroke (which increases moment of inertia and increases its equivalent parameter of mass) making it easier to fall on each downstroke.

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https://www.youtube.com/embed/VuqiiOj_Pj8?start=25&end=36

https://tinyurl.com/4e37vyh6