Quentin Matsys - AN ALLEGORY OF FOLLY 1510. oil on panel.

Mondeken toe
means keep your mouth shut! The fool’s cap, the bells, the donkey ears and the cock’s head are symbols of the fool and in fact professional fools at the time would use these as part of their costume. The puppet figure shown emerging from the top of the stick represents a marotte which was used by fools a bit like ventriloquists use a dummy. And on the forehead appears the stone of folly.