Love how she didn't do a straight line across the back of her head then cut the zigzag pattern into the shaved part. Using the zigzag cut as the defining line between long hair and buzz cut and then continuing with that pattern in varying, fading lengths, makes it a softer transition from long hair to undercut. More feminine, less like a bowl cut.
Style-Short hair updo for wedding or going out - so i didn't do EXACTLY this. instead i criss-crossed some pieces in the back and used bobby pins. my swirl at the neck wasn't as 'clean' as that and more to the side but it definitely added character to the 'do