These indentations are called coffers.
1:Violin
2:Viola
3:Cello
4:Double bass
If it’s the right hand spaces are FACE (f, a, c, e) from bottom to the top. The line notes are every good boy deserves fudge (e, g, b, d, f,) from bottom to top
Some elements are line shape value , color, proportion/ texture/ shading.