In music, it appears in the 4/4, on the first beat.
Answer: a famous painting
Pixie cut 1 is by Darxu on Deviant Art
Pixie cut 2 is by Derek Hetrick on Twitter
Mohawk 1 is by Ficeaxx (at least I think that's what the signature says) source is unknown
Mohawk 2 is by Little-Noko on Deviant Art