The Spotlight node can be used to place a spotlight-shaped texture onto the surface of an object (figure 1).
Figure 1: The Spotlight node applied to a scene object
Figure 2: The Smooth Voronoi Contours node and it's associated parameters
Orientation
Primary axis for the emission cone.
Direction or Target
Specifies the direction or target point, this parameter is ignored if orientation is set to surface normal.
Cone Angle
Width of the cone angle in degrees.
Hardness
Controls how abruptly the emission pattern falls of at the edges.
Normalize Power
Keeps the emitted power constant when the cone angle changes.