In these examples (with numbers 2, 3, and 5), you scarcely have to count. And you don't have to bother about functionalities or names of species.
(top, left) Apparently, the clock was established while the (merged) leaves arose.
(center and right) Parts in a ring are positioned on top of two parts in the ring below.
(mid row) Combinations with differentiation of a ring with numerous parts.
(bottom row) Mostly, 6 means
(left) 3 mirror symmetrical parts, or
(center) 2 rings of 3, and
(right) 10 means 2 rings of 5.