Cool nail designs come in many varieties, with the marble design being one of the most popular. This design is created by using cool water and three or more different nail polish colors. It is very simple and easy to do at home. You can create the marble design by using multiple nail polish colors, a glass of cold water, and a lid. Just pour a drop of any nail polish into the cold water one by one, use the lid to make vertical and horizontal stripes in the polish, then plunge your nail into it. Other cool nail designs include polka dots or stripes. All you need to create these beautiful designs is a nail pen. This is very useful for any nail art design and can be used to easily draw any shape you want.