The Nailasaurus: Day 9: Rainbow Nails (rainbow waterfall mani!) | "I used 20 different shades of nail polish in this nail art. Most of the time spent on this mani was just screwing and unscrewing the bottles!"
25 Fun and Easy Nail Art Tutorials | Style Motivation
Paint bright base coat. Paint black on top. Roll Q-tip down nail several times. From Nail It Magazine.