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What happens during the propagation steps of methane chlorination?

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In the radical chain reaction of methane chlorination, the propagation phase consists of two repeating steps that sustain the process.12

After the initiation step produces chlorine atoms, the propagation sequence proceeds as follows:

First step: A chlorine atom ( $\cdot$ Cl) collides with a methane molecule (CH $_{4}$ ), abstracting a hydrogen atom to produce a methyl radical ( $\cdot$ CH $_{3}$ ) and hydrogen chloride (HCl).1
Second step: The highly reactive methyl radical ( $\cdot$ CH $_{3}$ ) then reacts with a chlorine molecule (Cl $_{2}$ ), yielding the final product, chloromethane (CH $_{3}$ Cl), and regenerating a chlorine atom ( $\cdot$ Cl).12

Because the chlorine atom consumed in the first step is regenerated in the second, a single chlorine atom can facilitate the production of many molecules of chloromethane, characterizing this as a chain reaction.12