Why do some guitar notes look box shaped

Answer gutzon borglum was both a gifted painter and sculpture;

Idid the quiz. the true answers to this question is  2.michelangelo used the hatching technique of drawing parallel line close together  1.leonardo used the sfumato technique of blending and blurring chalk so edges nearly dissapear3.van gogh used a variety of expressive strokes to create different surfaces and textures. to the above answer, i got it wrong. i have copy-pasted from the question, putting the answers here.i hope this .  ~rosy67read more on -