LIGHT was primary in my consideration. All senses of "process" are (to me) based primarily on "thought-process"; and "thought-process" is based primarily on "memory re-call"; and that, as any memory process (all process finally) is electrical (firing of nerve connection) and expresses itself most clearly as a "back-firing" of nerve endings in the eye which DO become visible to us (usually eyes closed) as "brain movies" - as Michael McClure calls them. When we are not re-constructing "a scene" (re-calling something once seen), then we are watching (on the "screen" of closed eye-lids) the very PROCESS itself.