A projector of a light beam includes a first optical body movable along a frame for modifying its position with respect to an outlet lens and to a light source. A second optical body includes a first prismatic lens having a first number of twists and turns on at least one relative concave surface for generating a plurality of optical effects acting on the beam. A third optical body includes a second prismatic lens, positioned alongside the first prismatic lens, having a second number of twists and turns for generating a plurality of optical effects, individually or in combination with the first prismatic lens. The second and third optical bodies can rotate between non-operating positions, wherein the respective prismatic lenses are away from the light beam, and operating positions, wherein the respective prismatic lenses are positioned along a lighting trajectory of the light beam.