There’s a reason summer coffin nails, also known as “ballet nails,” are one of the most popular nail shapes in the mani world. They look great, reminiscent of the square fingertips of the ’90s and early 2000s (remember the manicure Britney Spears did in her “Toxic” video?), and the long, tapered shape Plenty of room for polish, art, glamour, and design.