illusionism, in art, a kind of visual trickery in which painted forms seem to be real. It is sometimes called trompe l'oeil [Fr.,=fool the eye]. The development of one-point perspective in the Renaissance advanced illusionist technique immeasurably. It was highly developed in the baroque period; Caravaggio's bowls of fruit included insects to enhance verisimilitude. American masters of trompe l'oeil include William M. Harnett and John F. Peto.