Square Peg in Round Hole

The scene: a FATHER and his thirteen-month-old SON in a living room. The SON is playing with one of those toys where you have to match different shapes to the corresponding hole.

SON: (struggling to push the red square through the blue round hole)

FATHER: Oh, son, son. The square goes in the square hole. Here, Daddy can help —

SON: (twists the square in such a way that it drops through the round hole)

FATHER: … Well, shit.

I’m not sure whether the toy is defective or brilliant.