the.com/nesting dolls

means A set of wooden figures of decreasing size placed one inside another, used literally as a toy and figuratively for anything that contains smaller versions of itself nested within.

from Known in Russian as matryoshka, from a once-common female first name Matryona/Matriosha, itself traced to the Latin 'mater' (mother) — fitting for a doll that keeps producing smaller dolls from inside herself. The toy as we know it emerged in Russia in the late 1800s, carved and painted by craftsmen inspired by a set of Japanese nested figures (said to be of the god Fukurumu) brought back from Japan. So the 'Russian' icon has a folk-tale origin that's actually half Japanese import, half Russian reinvention.