Some of the very first photographs I took were reflections, an oblique way to catch a self-portrait, like a side-eye glance.
Shiny surfaces that act like a mirror are often spherical, a garden globe for instance. This curvature in space/time gives a real sense of peering in from outside, from either direction; inside looking out or outside looking in.
Window reflections give you a side-by-side experience as you go about your business of doing this or that.
Shadows on the other hand absorb your physical form, flattening it into two dimensions, hiding any hint of our solid reality. Shadows are seamlessly attached to our feet and commingle with surrounding surfaces, stretching and shrinking.
These visuals escape the illusion that photography is a true depiction. Their elusiveness is a poetic telling of our ephemeral nature.