The simplest toy, one which even the youngest child can operate, is called a grandparent.

The humor comes from reversing expectations: a “toy” is usually something a child controls, not a person. By calling a grandparent the “simplest toy,” Levenson highlights how readily many grandparents allow themselves to be drawn into a child’s world—responding to small cues, demands, or games with warmth and compliance. The line also gently teases the grandparent’s eagerness to please, suggesting that experience and age do not necessarily confer authority in the presence of a charming child. Beneath the joke is an affectionate recognition of intergenerational bonding: the grandparent becomes a willing participant in play, offering time, attention, and unconditional acceptance.