In my intuitive studies of light and form, I find no conclusions except that light reveals itself in vision, hearing, sound, touch and emotion. I sense familiar relationships of proximity and tension strengthened
by light's presence, and sometimes identify an inarticulate void, existing in a "sea" of light. In this intuitive fame of mind, the void also generates an emotional response.
It also occurs to me that a most basic confirmation of our physicality is given us by light. And as a result, we intuitively honor the need to erect a grave marker that casts a shadow to remind us of an individual who doesn't cast a shadow any more.