Yes we always see cross contour lines on an object
I recommend avoiding details and shading the piece until its fully sketched in
you can blend charcoal with a piece of tissue if you use your fingers it will leave prints
if you are in the process of shading place a piece of paper between your hand and the paper to avoid smuging
you can use a slice of bread to remove the graphite like a stretch eraser
Timbre
( I'm only typing this to fulfill the character requirement)
The flute has the widest range of any instrument in the woodwind section
