: When the Sun shines on the Apple, it kisses one spot—the Highlight (the brightest point).
Start the lesson with a short tale to introduce the technical terms naturally: : A perfectly round Apple (or any simple sphere). : When the Sun shines on the Apple,
: The Apple is proud of its bright side, but on the side opposite the Sun, it wears a dark "velvet coat" called the Own Shadow . This shadow belongs specifically to the Apple and makes it look round and "heavy" instead of flat. : When the Sun shines on the Apple,