>>7727931
Yeah, that's just a reflection difference. The darkening has little to do with lighting being blocked. The same amount of light is just scattered over a larger surface area (plus some other minor stuff like fresnel reflections bouncing light away.

Form shadows are when an object blocks light from itself

Cast shadows are when something else blocks the light

They're both made up abstract terms and don't really have any basis in reality. They're just places where an appreciable amount of light can't reach.