Light direction - length and position of shadow

The angle at which light strikes an object will determine
the length and position of the shadows cast by that
object. The shallower the light's angle of incidence,
the longer the shadows. Extreme shadows on desks or
when reading in meetings, for example, can be very
annoying. Especially when hands or other objects cast
additional shadows onto the viewed object.
For right-handed people therefore, light should come
from a slight angle above left and from above right for
left-handed individuals.