Among the more commonly reported,[23][24] and more thoroughly researched, sensory features of hypnagogia are phosphenes which can manifest as seemingly random speckles, lines or geometrical patterns, including form constants, or as figurative (representational) images. They may be monochromatic or richly colored, still or moving, flat or three-dimensional (offering an impression of perspective). Imagery representing movement through tunnels of light is also reported. Individual images are typically fleeting and given to very rapid changes. They are said to differ from dreams proper in that hypnagogic imagery is usually static and lacking in narrative content,[16] although others understand the state rather as a gradual transition from hypnagogia to fragmentary dreams,[25] i.e. from simple "eigenlicht" to whole imagined scenes.
http://en.wikipedia.org/wiki/Hypnagogia
