Trending Coffin Medium Length Acrylics / Mix up your classic manicure by trying out one of these insanely cool nail shapes, including kylie jenner's coffin nails, subtle almond nails, and more. If would like a shape other than square you will need a medium length at minimum. Coffin Medium Length Acrylics - This is a favorite amongst those that prefer long nails and it's a cool shape if you want to try something different.