A set of matryoshkas consist of a wooden figure which separates, top from bottom, to reveal a smaller figure of the same sort inside, which has, in turn, another figure inside of it, and so on. Also called nesting dolls the casual observer would not realize that there is a doll within a doll at first glance. It is only upon careful observation that the viewer realizes that something is inside the nesting doll in hand.
Like the matryoshkas nesting dolls, this cache opens to reveal a container within a container which should be twisted gently clockwise to open and then gently counter clockwise to close.